Subterranea Britannica
subbrit.org.uk
subbrit.org.uk
https://en.wikipedia.org/wiki/Royal_Observer_Corps_Monitorin...
This short film from 1971 that includes scenes filmed in observation posts and a central bunker:
Circa 10 years ago I was involved in a project helping transition it from 80s phone exchange into a modern facility built to a good spec. Getting connectivity out there was painful and expensive; at one point it was backhauled wirelessly to Skegness!
http://www.secretscotland.org.uk/index.php/Secrets/BarntonQu...
This bunker would have been the Regional Seat of Government for Scotland:
https://en.wikipedia.org/wiki/Regional_Seat_of_Government
Given that its location and purpose wasn't a secret I imagine it would have been blown to bits in any conflict.
But then, hey, Britain. We have a load of secrets that aren't technically secret but we'd rather you didn't know and would take a dim view of you trying to find out. Especially true during the Cold War (see e.g. Backbone, etc).
There was a new RSG type bunker at Cultybraggan near Comrie but, with impeccable timing, that wasn't completed until 1990!
We regularly have people visit from all the way up and down Hitler's 'Atlantic Wall' and they really like the number and condition of the bunkers here.