Great article Arzosah, thanks for sharing.
I paid a visit to Kelvedon Hatch just two weeks ago. I live less than 15 miles away, so it's on my radar in the case of SHTF

Although having said that, it's not quite so 'secret' any more - there are brown road signs everywhere that read 'Secret Nuclear Bunker'!
VICE did a (somewhat childish) report on it a couple of years ago, but it includes some good photos:
https://www.vice.com/en_uk/article/avyn ... -essex-591
If you're nearby I'd recommend a visit - it's an impressive feat of engineering and really gives you a feel of what it was like to live with the threat of nuclear war. It's also a good place to pick up some prepping tips, if you're preparing for a nuclear strike (personally I'd rather be vaporised). It's run with minimal staff, so you just park up and walk straight in to the main entrance - feels a bit like you're trespassing!