What is this ?

[dr hue]

St Peter's Church, Bushey

1Km from box S5 stated location.

What is this on the triangular island near the trough ?

[peterjohn]

I got extremely excited over a similar object in Bracknell a while back ..... 

https://tardisbuilders.com/index.php?topic=5909.0

[alexcutler]

I'd love it to be a prototype Police Box.  But there might be a much simpler, more mundane explanation:

Given it is inside the churchyard - could it simply be a shed for the grave-diggers?