Hi Guys,
Not sure if you are planning any road trips in the near(ish) future, but if the UK is on your mind then I would highly recommend Dover Castle. I visited yesterday and it has a very well preserved series of tunnels used during the war, including for organising Operation Dynamo with equipment to boot as well as a military hospital which has been equally well preserved. Keep up the great work as always 
I whole heartedly agree - just not far away are some Home Chain radar sites and some (almost same era but similar design) masts still standing.
The problem is in getting permission to film. I looked into it in the past, the process is Byzantine and not mildly irritating. We gave up. Maybe Timeghost is more determined, but for us it wasn’t worth the hassle, especially from the US. (They insist on a recon visit before the actual filming)