Remind me, was the Duke of Windsor an actual collaborator or merely a sympathizer (as many in the UK and US back then)?
Agree on John Lithgow, wonderful performance! I also love the actor that plays Tommy Lascelles (one day I'll read Lascelles' diary).
The actor who plays Tommy Lascelles also looks like him - and what a superb performance.
Re the Duke of Windsor, he was, I think, to some extent, both collaborator and sympathiser, though the edges between both roles are blurred.
While he was certainly a Nazi sympathiser, (and that sneering, bitchy, self-serving and self-pitying performance turned in by Alex Jennings is utterly spell-binding - the voice-overs of his scathing, self-absorbed and self-serving letters read while he is about his business is brilliant drama - simply superb), when I read books such as The Rise and Fall of the Third Reich, it was made clear from German sources (that the Americans had by then) that he was certainly extraordinarily sympathetic to the Nazis, and was clearly in line to be restored to his throne as King (with, I assume, his complete approval) had the Germans ever managed to conquer the UK.
Other documents pertaining to this, if memory serves, were sealed (by the British) under a 100 year rule - rather than the normal 30 year rule - which tells its own story; if this material was benign, I doubt it would be sealed, or would have been sealed for such a long time.
However, US sources (based on German sources) - which was made clear in the episode - and German sources are not sealed, to my knowledge.
Nevertheless, enough seems to be dribbling out, or seeping out, from sources previously difficult to obtain access to, to suggest a greater enthusiasm for what the Nazis had to offer the world (driven, in part, by bitterness at his fate post Abdication - they were to be the means whereby he could be restored to his throne - the controversy, if and when that emerges, may well lie in the details of whatever deal may have been discussed or struck with the Germans to bring that about) that was officially admitted at the time or for a good while later.
I also suspect a sort of gentle and subtle softening of public, and historical, opinion, in advance of the release of this material, in terms of acclimatising them to the extent of his links with (and enthusiasm for) elements of the Nazi regime.
My wife says the critics have not been impressed with this, my guess is because it's on the slow side, not as flashy as The Tudors, but I believe they are maintaining a higher historical standard. As with Downton Abbey it's fun to see interpersonal conflicts raised to high level of intrique such as Elizabeth deciding her husband will manage her corination and being told that's quite impossible. 
