Just rewatched it, and must be one of the best movies from the last decade.
Did they get some kind of "permission" from Queen Elizabeth II to make this movie? I can't really imagine they could have made it if she was totally against it, or?
You don't need to get permission to make films or documentaries about any member of the royal family. If things upset them it they would get their lawyers on it pretty much like they do with the newspapers occasionally.
Before it was released to the public there was a private screening for the Queen so she knew what was in it early enough to get something edited out if necessary.