Mark 1, Mark 2, Mark 3?

[hb88banzai]

I think there may have been a fair amount of mk1 redressed boxes that had a similar look, as they used leaded window panes, notcast iron types:

Nice pics. I'm curious, though - how sure are you that the last picture is actually of a Mark 1 redressed as a Mark 2?

Other than the windows it looks all the world like a Mark 2 to me. The low Lock position (not trivial to change), the deep and wide Top Sign boxes, the height and spacing of the Roof steps - all look distinctly Mark 2 (Barnet type rather than Crich).

The only Mark 1's I've seen, even the one that was updated for the 1936 Olympia Exhibition, all kept Mark 1 attributes for those features (among others not visible in this low-res pic).

Am I missing something?

Regardless, the mostly pebbled window panes and the apparently black on white (or light blue) top sign graphics (probably using a serif typeface like the Olympia Exhibition box and another I've seen pics of) do seem to point to it being a transitional period picture of this box. Very cool.

[peted]

Hi hb88banzai.
I don't refer to this type of box as a mk1:

These were the prototype timber boxes that that were used in Richmond, Wood Green and Barnes.
(See my PDF http://razorcuts.webng.com/a_history_of_the_british_police_telephone_kiosk.pdf)

The first mass produced concrete Met boxes looked like this:


They used Times roman style type on the lintels, had the much wordier phone panel below the telephone door:


And the St John's badge on the adjacent panel, one lower than normal. They had leaded window pane dividers, rather than the cast iron hopper style. Dinky style layout, basically.
We figured out that they redressed this type of box to look like mk2's when someone posted a photo (it might even be a clearer shot of this box from the documentary) that clearly showed screw holes where the old telephone panel had been removed from the panel below the phone door.

[hb88banzai]

Ahhhh, now I see where you are coming from. I don't know why, but I had always considered the "prototype" wooden boxes as Mark 1's and the "prototype" liveried concrete boxes as just the first version of the Mark 2's since the later changes were largely cosmetic, save the major differences between the Barnet and Crich style boxes.

You certainly are the expert on the matter - I loved your old Police Box site. I don't know if I was misremembering or if things were a bit less clearly delineated back then.

Curious - has there been any correlation found between your Mark 1 and 2 designations and structural changes between the observed boxes like Barnet vs. Crich? Otherwise it would seem a more cosmetic change than say between the Mark 2 and radically different Mark 3's.

Have you given any thought to including the "prototype" wooden boxes into the mainstream of Mark designations? I mean it seems like usually it goes beyond calling something a prototype if multiples of the exact same model are actually made and deployed in the field for an extended period of time, even on a trial basis. Wonder how many wooden prototype Met Boxes were actually made (it certainly seems like the Olympia box was one of them). Of course then there's the fact that in some ways the TARDIS has more in common with those boxes as they were actually made of wood.

The Mark 0?

Just a thought.

[peted]

Mark 0 works for me! It's simply a historical thing.
I cooked up the whole mark thing very early on when I realised the Glasgow boxes came first and looked quite different. The that lovely pic from 1936 turned up and I had to go back and do some more homework. There are basically two distinct looks for the met and the differences are mainly cosmetic. It looks to me that simply took the old instruction panels away, fitted new ones in the telephone door with simpler instructions and moved the St John's badge. I think they left the lintel signs because that was too much like hard work, so you get these 'hybrid' look boxes - leaded windows, with dark type faced lintels, but mk 2 style telephone panels. I don't think they're structurally different at all, but it makes sense - the mk1 met looks decidedly 1930s whereas the mk2 looks very 1940s - the typeface looks a lot more modern.
The Glasgow boxes are certainly structurally different. The only differences I've seen amongst Met boxes is the height of the roof stacks.
I think the notion that police boxes are wooden in the Dr Who world was perpetuated by Terrance Dicks in the Target books. When they built the Brach prop, they certainly tried to make it look like concrete with the artexing. The Yardley Jones made no attempt to look like wood - there was no graining present anywhere. I think RTD etc, like us, grew up thinking that Dicks was gospel, and so the 'stuck in the shape of an old wooden police box' myth stuck. What I do find fascinating is the whole telephone panel being blue with white writing on. At first I thought this was born of mistake - the hurried changes to the Brach prop around Space Pirates time, with the the white type face on a dark panel. But then I was sent this pic, in about 1997:
EDIT: orig scan was too big to attach so I've had to shrink it.

A MK3, which clearly shows a blue telephone panel with white text. And that lamp!!?? Looks like the Blackwall tunnel box. We simply don't have enough pics of these type of boxes in their original livery at all. I have the camden pic showing a mk3 with a traditional fresnel beacon and also the original royal blue. But this thing is weird - but did they look like this all over the place? Or was this the oddball? I think the window in the door thing we see at the Hendon mk3 was a one off. I suspect it was this look and colour scheme that inspired the TYJ design. Wish we had a better pic of this box, or others like it, if there were any

[geminitimelord]

Very interesting photo and information.

I really like seeing the White letters on blue for the pull door sign.

[peted]

I knew I'd read it somewhere...
quoting Ironageman (a brilliant source of info):

The original 1920s (Mk 1) boxes were timber on a concrete base, so I imagine that they brought one of those along (possibly the Hendon training one?) giving it a timber base for the exhibition... Then the signage was updated on both timber and concrete boxes - on pictures of the Barnet box, you can just make out where the old telephone plaque was, below the telephone door.

There must be some good pics of the Barnet box on here somewhere, showing those screw holes...

[hb88banzai]

Yes, I had read that post from Ironageman recently as well, so it had struck a neuron when you first mentioned it.

But of course he also calls the original timber boxes Mark 1's as well. In fact I just looked through an archived version of your old Police Box Website to refresh my memory (talk about a nostalgic stroll through the past) and some of your comments under the pictures in the "Dead Boxes" page label as Mark 1's what we now know to be pics of the timber boxes, specifically mentioning their very unusual top beacons.

I knew I wasn't imagining things. But then that was probably written before we had the higher resolution versions of those pics that showed that they were definitely made of wood.

On the topic of the differences between the Barnet and Crich style boxes, I think that the differences are actually quite major in some ways. The pillar details (height, top cap (size & height), and edge moulding), the roof profile, the sign boxes (narrower, shallower and possibly of different construction) and the vertical seams in the pillars above them that appear to represent a major difference in the all important ring beam - these all point to a semi-major design and construction revision, both cosmetic and structural (the ring beam being such a major structural component).

In a perfect world, the introduction of the Crich type box (as it is almost certainly the the later model) would exactly correspond to the other differences that would constitute the Mark 2 (continuing per your present designations above) so that we could attribute the Barnet type to be Mark 1 (irrespective of sign and other cosmetic changes) and the Crich type to be the Mark 2. The changes in signage and windows, etc., could be designated by a sub-mark like Mark 1a for the first version with POLICE (and the lower positioned panel signage), the Mark 1b for the revamped serifed blue letters on white field POLICE PUBLIC CALL BOX transitional version, and the Mark 1c for the final version dressed as a Mark 2. Too complicated? Of course it could also be completely off base depending on when the changes actually occurred.

On the subject of the longevity of the Mark 0's in service, while rummaging around on that archived Police Box Website I took another look at something and it immediately set a whole bunch of alarm bells off in my head. Here it is - a picture taken during the height of WWII:



Now look at those top signs! That, unless I am quite mistaken, is a Mark 0 with the more modern Mark 2 signage. The very flat sign box with the additional framing around the sign plate and the drip flashing on top of it, the leaded windows, even the very sharp edge on the pillar moulding all scream the timber boxes to me. In fact, is the blob in the lower corner one of the original style knobs instead of a bow handle? If it is a Mark 0, then it is interesting to see that they revised the top sign in an entirely different manner than they did for the Olympia show transitional version. More importantly, it means that at least one of them was in service for over 10 years!

EDIT: The above pic is much more detailed than it appears in the size it gets rendered (in Firefox, anyway). Enlarge the page (or download the image and view and enlarge it separately) to see it in all its glory. It's really quite an interesting pic, despite the grainy nature of the newsprint half-tones.

[hb88banzai]

I knew I'd read it somewhere...
quoting Ironageman (a brilliant source of info):

The original 1920s (Mk 1) boxes were timber on a concrete base, so I imagine that they brought one of those along (possibly the Hendon training one?) giving it a timber base for the exhibition... Then the signage was updated on both timber and concrete boxes - on pictures of the Barnet box, you can just make out where the old telephone plaque was, below the telephone door.

There must be some good pics of the Barnet box on here somewhere, showing those screw holes...

Found it. Originally from Ironageman (hope he doesn't mind me posting it again here):

[peted]

Hi hb88banzai,
You're absolutely on the nail about not having hi-res pics of those boxes at the time. It's funny that much of what I wrote about the boxes back then I was 'busking it' based on the information I could unearth at the time, with a little bit of guess work thrown in - those early photos clearly show people in 1920s clothing therefore they must be the first boxes etc etc. Things I wrote became 'gospel' in some ways and whereas I was quite happy to move the goal posts based on new info, others often weren't - I remember I got a snotty email from someone going on about how I was wrong - this was definitely this mark and that box was so and so - when I'd made up these arbitrary guidelines in the first place . It sounds like you've spent more time actually studying the intricacies of the mark 2 variants than I have, which is great stuff - Ironage has every nook nd cranny of the barnet box down and if someone has done the same with Crich, it would be interesting to know exactly what they are - but on a fundamental level the design is the same I feel pillar capping differences and stack depth are small (but yes, significant) differences - variants of the same, probably brought about by having to replace original moulds due to damage, or even sourcing the work to another casting company? who knows?
That air raid photo was one of the very first pictures I was sent when I began the website and it's been a loong time since I looked at it. You are spot on there, it does tell us an awful lot if you look at it closely - the almost flat lintels, the drip cover, the lock placing, the pebbled glass in 5 out of 6 panes... this is certainly a Mark 0 (it's sticking already!) repainted. I WISH I had the original picture I was sent, but shockingly I cannot find it - I moved the caption to underneath the picture when I shrunk it down and made it a GIF (what was I thinking?) The caption was originally to the left, a common picture of the barnet box was on the same page I think, and this picture was the main one. If I'd taken note of what book it was from, we could find it again. For me, the most siginficant thing in this pic, in those very early days, was that the window frames were not white - so I'd thought 'ah, the tardis is right after all'
Soo, this is how I'd summarise what we know for the Met boxes:
Mark 0 - wooden prototype (we still have no real idea what colour these things are! Ironage guessed at light blue, but they could be white!) Introduced in 1929 - no idea how long they lasted.
Mark 1 - concrete box, the 'dinky' layout - clear telephone door, wordy panel underneath, leaded windows, lintels with dark roman script. Very 1930s looking. Colour looks dark on some photos, lighter on others. (The Glasgow boxes are the 'real' mark 1 in my eyes - they came before met boxes and have significant design differences, but we're talking met here)
Mark 2 - Barnet/tardis look. Very 1940s looking to my eyes. I imagine that some boxes were made looking like this and some were redressed mark1. The differences between mark1 and mark2 aren't overly significant if we are honest - they are pre cast concrete, with a fresnel beacon.
Mark 3 - we have seen 2 variants of this box - the Camden box and the older photos of the Hendon mk3. Royal gloss blue, white trim, fresnel beacon, then there is the Heathrow version - lighter blue, blue backed telephone panel with white type, no white trim - some have the thin domed glass beacon (reminiscent of the Tom Baker opening titles) and also deployed on the blackwall 'fire box'. Mark 3 types look decidedly 1950s to me.

[hb88banzai]

Hi pete d,

Yes, you did some quite amazing things with the little info available at the time. It's a testament to this that the whole "Mark" system has become used by just about everybody as if officially handed down from the Met themselves.

I think you might be a tiny bit off, however, about the Glasgow boxes being the first concrete boxes of the Met pattern. Yes, Glasgow had boxes from the 1890's on, but according to the sources I've seen (and recently reviewed), prior to 1931 they were all the original hexagonal cast iron boxes like this one:



A very cool design in its own right (and very similar to the earlier Chicago Police Box pattern), but from what I've been able to gather the first concrete boxes of the Met pattern appeared in Glasgow starting in the early 1930's on the order of Glasgow's Chief Constable Percy Stillitoe, who didn't even take office there until 1931. He was responsible for starting the Police Box network in Sheffield a couple of years prior, but they were of the garden shed variety.

According to the seemingly rather good "The Police Signal Box: A 100 Year History" put together by Robert W. Stewart (though more concerned with Scottish boxes), the first concrete Glasgow boxes were erected in 1932, which is a bit after the start of the erection of the first concrete Met boxes some time in 1930 or 1931 (with the first Met "pilot program" timber boxes being described in various places as first being installed in either 1928 or 1929 (even the Met's own website seems to imply 1928, which I think is wrong)). That would make the Glasgow boxes a derivative of MacKenzie Trench's Metropolitan Police design (IIRC the plans are dated 1929) and not the original Mark 1 at all.

Here's a link to the Box history I'm referring to:

http://homepages.eee.strath.ac.uk/r.w.stewart/boxes.pdf

As I said, it mostly covers the origins of the Glasgow network, but does give some details (though a bit dated and with a few errors) on other UK boxes. A very interesting read, regardless, with some nice illustrations (especially of the older boxes).

[hb88banzai]

On another note -

(snip)

- but on a fundamental level the design is the same I feel pillar capping differences and stack depth are small (but yes, significant) differences - variants of the same, probably brought about by having to replace original moulds due to damage, or even sourcing the work to another casting company? who knows?

(snip)

Soo, this is how I'd summarise what we know for the Met boxes:
Mark 0 - wooden prototype (we still have no real idea what colour these things are! Ironage guessed at light blue, but they could be white!) Introduced in 1929 - no idea how long they lasted.
Mark 1 - concrete box, the 'dinky' layout - clear telephone door, wordy panel underneath, leaded windows, lintels with dark roman script. Very 1930s looking. Colour looks dark on some photos, lighter on others. (The Glasgow boxes are the 'real' mark 1 in my eyes - they came before met boxes and have significant design differences, but we're talking met here)
Mark 2 - Barnet/tardis look. Very 1940s looking to my eyes. I imagine that some boxes were made looking like this and some were redressed mark1. The differences between mark1 and mark2 aren't overly significant if we are honest - they are pre cast concrete, with a fresnel beacon.
Mark 3 - we have seen 2 variants of this box - the Camden box and the older photos of the Hendon mk3. Royal gloss blue, white trim, fresnel beacon, then there is the Heathrow version - lighter blue, blue backed telephone panel with white type, no white trim - some have the thin domed glass beacon (reminiscent of the Tom Baker opening titles) and also deployed on the blackwall 'fire box'. Mark 3 types look decidedly 1950s to me.

Hope this doesn't seem like belaboring things, but I'm just wondering - if you consider the roof and sign box changes to be essentially cosmetic and not meriting "Mark" change status, then what qualifies the sign position and window changes to be the criteria for "Mark" change? I mean, aren't they essentially even more cosmetic than things like roof, pillars, sign housings and ring beams? It seems far easier to change things like windows and signs than it does make whole new molds, etc., and thus they almost seem less significant, even though perhaps a bit more obvious to a casual observer.

Maybe it's just the latent engineer in me, but I always think of these things from a design and structural point of view - what engine is in the Spitfire or how the airframe is changed, or even a differing silhouette determining the change in "Mark" rather than how it is painted, or where they put wing insignia or the build plaque.

Please don't take this the wrong way, but if both the above are essentially cosmetic, then it seems to me even more logical to ascribe the timber boxes (being made of an entirely different material with consequent changes in design) as the real Mark 1 (the first physical embodiment of the Met design), with all the concrete boxes of the original MacKenzie Trench pattern as the Mark 2 (Glasgow then possibly being something like the Mark 2a as it's clearly derivative) and the vastly simplified later ones still getting the Mark 3 designation. That would even leave room to make the original 1929 MacKenzie Trench plans (which have really NEVER been faithfully followed) the Mark 0, or prototypical design.

This would really just mean that the pre-Mark 3 concrete boxes (all designated Mark 2 in this scheme) had essentially Mark 1 (timber) livery that evolved over time to that we are all familiar with, now immortalized by the TARDIS. (I note that upon review of many of the more technically minded Police Box threads on the old site that it seems like this is the nomenclature many (perhaps most) people were using over the past five or so years - rightly or wrongly this appeared to be more or less what people thought was meant by the various Mark designations.)

Of course, this is just if we wanted to keep things simple, rather than actually trying to account for all those changes in the Mark 1/2 design over time - which upon further review of all the pics posted is far more varied and complex than I had at first imagined (or perhaps hoped) - - Crich, Barnet, Barnet w/ High Roof & Flatter Signs, Barnet w/ Short Pillars, etc., just to describe the few I've noticed so far. Even with the actual Barnet box there seem to be inconsistencies between the right and left sides in the front view, at least as she appeared in her final years, so coming up with a comprehensive taxonomy could be quite problematic (especially with the limited data available).

Does any of this make sense to you, or am I just being overly persnickety?

[peted]

I hadn't realised the hexagonal boxes had been cast in concrete later on... Funnily enough though, when you mentioned the Glasgow GMT style boxes came in 1931, it rang a bell, so I went back to my own PDF (!!!):

1931 - Percy Sillitoe becomes Chief constable of Glasgow Police force. By now the pioneering network of cast iron Police Boxes are in need of a revamp and many more boxes are still required for the growing industrial metropolis.
Sillitoe rebuilds Glasgow's police box network in the exact same style of London's new cheap mass produced hard wearing low maintenance design. 
However, the one identified weak spot in the Met's design is rejected in favour of a more robust one. The telephones that were clearly on show in the metropolitan design were being stolen or vandalised, the units being ordinary domestic style dial telephones that could easily be removed from the boxes with a pair of wire cutters and a screwdriver. Glasgow Police looked to the Swedish firm Ericsson to come up with a design for the phone panel that was vandal and theft proof.

So I should have remembered that! I think this information came from Ericsson (or rather, someone who used to work for them) - I have somewhere detailed drawings of how their speaker flap design works - there's a snippet on page 7 of my doc. They were manufactured in Beeston, which is just up the road from where I live.

[peted]

Of course, this is just if we wanted to keep things simple, rather than actually trying to account for all those changes in the Mark 1/2 design over time - which upon further review of all the pics posted is far more varied and complex than I had at first imagined (or perhaps hoped) - - Crich, Barnet, Barnet w/ High Roof & Flatter Signs, Barnet w/ Short Pillars, etc., just to describe the few I've noticed so far. Even with the actual Barnet box there seem to be inconsistencies between the right and left sides in the front view, at least as she appeared in her final years, so coming up with a comprehensive taxonomy could be quite problematic (especially with the limited data available).

Does any of this make sense to you, or am I just being overly persnickety?

No, not at all - it makes perfect sense to be honest - the difference between what we have come to think of as mk1 and 2 are simple things such as colour schemes, peripherals and dressing details etc.
Because we don't know how many boxes were made from timber it seemed wrong to call it a mk1, as it implies they were rolled out across the board, so to speak. There may have been 10, 20 or a hundred, we don't know. But it's only a point of reference, so it shouldn't be an issue. Whatever fits best.

On a side line - when I wrote about the Glasgow boxes improving on the met design with the Ericsson flap activated phone, they of course carried another clever modification that I should have mentioned. In the Met boxes, the bell (for when the phone is ringing) is inside the box on the back wall, making it hard to hear at a distance. However, the Glasgow boxes had the ingenius idea of placing the bell on the very top of the beacon, making the sound of the ringing phone much easier to carry over distance. I'm not sure that many people realise that that's what the dome of the beacon on a Glasgow box actually is - a bell.

[hb88banzai]

(snip)

On a side line - when I wrote about the Glasgow boxes improving on the met design with the Ericsson flap activated phone, they of course carried another clever modification that I should have mentioned. In the Met boxes, the bell (for when the phone is ringing) is inside the box on the back wall, making it hard to hear at a distance. However, the Glasgow boxes had the ingenius idea of placing the bell on the very top of the beacon, making the sound of the ringing phone much easier to carry over distance. I'm not sure that many people realise that that's what the dome of the beacon on a Glasgow box actually is - a bell.

I suspected as much when looking at the pictures of the Glasgow boxes and hearing somewhere that the beacons had a bell in them (though in some cases people thought it was the first Met boxes that had them at some point - possibly the timber ones).

On that note - you know, I'm beginning to suspect that those "reactor" type tops originally on the timber boxes were rotating beacons. Something about the shadowy workings visible in some of the pics stir the imagination.



The bottom half of the sphere is opaque (probably metal) with a cylindrical can at the bottom where the wire cable goes in, while the top half is clear (before Perspex came on the market, so probably glass) - and inside there appear to be equally spaced dark bits arranged in a circle.  Always possible it is a bell, of course, but it seems suggestive to me of something that rotates. Wish we had a source in the GPO who could tell us (as I understand the just about all the signaling apparatus was sourced and installed by them).

Either way, looks like they simplified things for the concrete boxes. Whether because of cost, efficiency (ie, perhaps not enough light), or reliability is unfortunately not known. Still, quite intriguing.

And also note that the roofs on the timber boxes actually came to a point (at least before the hole was made for the cabling for the beacons). If you look at the below pic (erroneously tagged as taken in 1926 by Ghetty Images) you can see it is of people (one cropped out of image) checking out a timber box that has just been erected, and before the GPO has installed any of the hardware (no handles, signs, or beacon).



Wish we had a real date for this pic. I suspect that whatever year it was (most likely 1929 based on the most accepted start date for the pilot program), it was possibly late summer or early fall as there are still leaves on the trees and yet, though newly erected, there are still a few fallen leaves visible on the tops of the sign boxes.

For reference (in case somebody knows where this was) here's a lower res version of the full pic -



Also interesting to note about these boxes is that the stencil-type characters for "POLICE" on the top signs are actually cut through the wood or press-board that part of the sign was made of (rather than being painted or screen-printed onto glass), with the presumed glass backing on the other side not being visible in these pics. This  backing glass was probably blue tinted like the bottom center panes of the windows since if frosted or white they would probably be visible to some extent, not providing as much contrast as is seen in all the photos.

EDIT:  I very much doubt these things were any shade of white. As above, all the pics with signs visible show a marked difference between the white of the phone signs and the grey of the boxes. Based on relative brightness of B&W pics, I suspect (like Ironageman), that these were fairly light medium blue - perhaps a touch lighter than the later light-medium blue of the Met Police Posts. By all photographic evidence available it appears that the same (or nearly same) shade was used for the first concrete boxes (and similar to the lighter shades the Crich box has been painted in the past).

Also of note is that in the only picture we have of the interior of one of these boxes, there is no bell visible in the position that they were located in the concrete boxes - between the two windows on the back wall.



In fact, instead of a smooth wall there they have an extension of the outside center divider. So, either the later large type bell was located elsewhere in the cabin, or there was one in the top beacon housing, or (more likely to my mind) they simply used a separate regular old No. 1 bell set (similar to the NST phone door telephone w/o receiver or transmitter) for the candlestick phone either in the pillar-side inner recesses of the Phone Compartment or immediately under it (the inadequacy of which would explain their change to the big wall-mounted version in the later boxes). Such a bell set would be necessary regardless as it also houses the subset ("network" in phone parlance) necessary to make the candlestick work (a candlestick phone being just a glorified switch and handle/holder for the transmitter and receiver with all the guts that allows it to actually work housed elsewhere).

Also, I don't really think there is enough room in the "reactor" housing for both a beacon (especially a revolving one) and anything like the size of the Met or Glasgow wall bells (I seem to recall the Glasgow box at Avoncroft having a wall bell). A single large bell is possible, but would have to be mounted inside the lower portion of the sphere, mouth-up, with any support for the light beacon and bell clanger running up the center, which sounds way too fragile a setup to me. So, even if there was a bell up there it would likely be around the same size as those in the No. 1 bell set, so not very loud on its own, and though possibly useful as a repeater it would still be a bit inadequate.

I suppose a siren up there is possible (too loud to be inside), but again this would take up considerable room unless they could somehow make it coaxial with the (spinning?) beacon mount. Unlikely, and regardless, a siren seems a bit too obnoxious a device to have been used in this type of application, but who knows.

[starcross]

I suspected as much when looking at the pictures of the Glasgow boxes and hearing somewhere that the beacons had a bell in them (though in some cases people thought it was the first Met boxes that had them at some point - possibly the timber ones).

...before the GPO has installed any of the hardware (no handles, signs, or beacon).

Also interesting to note about these boxes is that the stencil-type characters for "POLICE" on the top signs are actually cut through the wood or press-board that part of the sign was made of...

...they simply used a separate regular old No. 1 bell set...

Also, I don't really think there is enough room in the "reactor" housing for both a beacon (especially a revolving one) and anything like the size of the Met or Glasgow wall bells (I seem to recall the Glasgow box at Avoncroft having a wall bell).

Hello Fellas,

This is a really great topic you've got going on, and although you would think I'd be in on it; My area of research focuses more on the Police Posts so all my Box information is incidental. As an aside I've got a article in the works for a photographic timeline for the Piccadilly circus Police Post trough the various decades, which is similar to this topic.

However that being said I can contribute to a few of the points being made about the Avoncroft Museum Glasgow Box.  

1) The beacons did indeed have a bell, no idea how that works unfortunately as the mechanism is missing from the Avoncroft models. Well the red Pillar doesn't have the bell mechanism. I was precariously perched on a ladder and neglected to properly check the Box while I was up there. However I know that it doesn't ring because a common GPO bellset is located inside the box.

This is the Beacon on the top of the Box:  


And this is the mechanism located inside of it, as mentioned the clapper is missing and so this Pillar is silent while ringing.


I suspect that it is the same with the Box and that is why they put this bellset inside of the Box


You can hear the ringing in this video of the Avoncroft Museum Box Ringing.

2) The signs do appear to come from the GPO or at least they made the ones for the Police Posts. The Telephone door sign I have posted here is marked as "Post Office Engineering Dept".

This is the title block information, although I had to add in the title for the glass as it didn't have it marked.


3) As for the Stencil style POLICE sign, It really does seem like the same sort of style as the Crowns on the London K2 telephone Boxes. I'm not sure exactly what date those are from, but it might be a GPO applied style.
There probably was no glass behind these and were most likely meant to ventilate the inside of the box. Later boxes I believe had the vents elsewhere, such as the glasgow boxes having the vents located below the signs on the sign box.

4) There was some talk further up about the ericson flap speaker grill. At least at the avoncroft Box they have the speaker grill functioning but the guts have a modern telephone set to speaker phone behind the grill.



[Edit Addition]
It took me a while to find but this is the correct base for the Communications inside the Glasgow Police Box.
Notice the notch on the one side? That would have been where the telephone the Police Officer would have used. Its really is in a crazy position and I suspect it would have been awkward to use? Maybe they had a different cabinet and configuration over the main unit instead of the Pillar covering?



[Edit 2]
After yet more research I turned up the photo below on the British Telephones Website. It has the photo labeled as a Kiosk Unit - Police Side View. I always assumed this was for the Pillar but a Kiosk usually tends to mean a Box of some sort?

It does lead to some narrowing of dates for the Glasgow boxes in the Mark Discussion however. So the earliest they could have been made was 1932 from the use of the speakerphone. And we can get an idea of how the internal telephone would have looked as built in the 1930s.  The light although odd would not have been out of place because the police boxes had flashing lights according to the 1937 GPO diagram "DRG PA 364 - Kiosk Equipment Layout".



You can find out more about the Ericsson speakerphone on the connected earth website. An excerpt says "The patent for improvements in or relating to police, fire and ambulance telephone call systems was submitted by Ericsson in 1931 and accepted in 1932."

Which makes sense as the Edinburgh Police Boxes that use this system were installed in 1932. The design for the Pillar version went out of style in London in 1938 when they made the first rectangular Police Post to accommodate more storage. They also moved away from the speaker because people were more familiar with the use of the Handset telephones by then and thus a change in design to the 200 series telephone.

Although the information board at Avoncroft Museum indicates that the speakerphone was indented to prevent theft of the handset telephones as they could be used for home use. Although in 1932 that sounds like speculation rather than fact as I imagine home telephones were not exactly that common. I've read that people would rent them from the GPO during that era and not own them. It would be a bit awkward to show up with a telephone with no dial and ask to be connected to the network surely?

Anyway I hope this wasn't too image intensive, As always larger versions are available on my filckr photostream.

Cheers,

~Starcross

ps: I hope making a massive post script additions aren't a hassle. Who knew I'd have this much to say?