UK Government Bomb Shelter
Perhaps, but WWII vintage in Dover unless I miss my guess. I cannot imagine what use a gun embrasure fitted with a standard double glazed kitchen window would have been.
Amusing though Peekford.. From what I have seen with my own MKI Eyeball in the UK, to a documentary of the Greenbriar's 'big secret', below ground (the bit what mattered), they were very much built to the same standard. They were building the huge Greenbriar complex anyway, and so a few 'extra' amounts of stuff & men would have gone completely unnoticed.
Black Pudding is now on three threads. Is this an irrelevant record?