As it turns out, Northampton also had Police Pillars (PA1).
I'm not sure if they moved to the PA3 style just yet, it only takes one photo or postcard to confirm it after all.
This PA1 Pillar shows up on Gold Street in 1955.
Source:
francis frith
Here is the map extraction from 1963 confirming the location.
The photo is looking due West down Gold Street as seen from just in front of the church.
Another PA1 Located just a Block East of the Gold Street Pillar.
This one is in front of the Guild Hall, hidden in the photo by the Motorcycle, in 1955.
Source:
Francis Firth
The Map Extraction from 1963 show the PTP in place.
Here is another PA1 at Mayorhold in 1959.
Source
The Map extraction from 1963.
It appears the photo was taken looking west.
Another Pillar indicated at the Northwest Corner of Towcester Road & Rothersthorpe Road in 1963, per the map extraction.
I also have questions about what they call the "Police Office" on the island at the junction of Parkfield Ave & Gloucester Ave.
Its possible this was a tiny brick building, or maybe it was a Box as in the first photo. I'm haven't found a picture to confirm what it was. However the Island doesn't look all that large.
