Kenley Building
Hi There N Silver if you are still 'on thread', if you can be a bit more precise re the location of said windowless building I may be able to help.
I was in your part of the world early in the year, but you must have been around Kenley just as i was joining 450 ATC .
The Burntwood lane structure is a post 1940 OP/antiaircraft elevated platform (same as Brooklands) no doubt built as a result of the low level Donier raid.
If you PM me I will send you my latest aerial view of Kenley plus a few notes.
I to remember the Boydon End Café at Hayes Lane, and the staff of 615 GS used the Roundabout Café when Kenleys catering facilities finally closed.
Great days driving an Austin 1 Ton 4x4 open back to the NAFFI full of course cadets,H&S what was that; I think we called it common sense. PP