I thought the lack of real information about what Blunt was up to in post war Germany where he was sent supposedly to collect letters from Queen Victoria, but may have been collecting (Looting?) valuables was interesting . I hadn't heard about that before. It might explain why he was never charged with anything. I've just read a book called "Witchfinder" by Andrew Williams. It's set in that era and it tells how the CIA become involved, trying to find the 5th man, it later has the CIA with a folder on Harold Wilson. It's fiction but based on some facts.
There was a brilliant BBC drama in 1983, written by Alan Bennett and directed by John Schlesinger. It starred Alan Bates as Guy Burgess and the excellent Coral Browne who played herself Highly recommended - but it is 40+ years since my younger self watched it!