I binge watched it yesterday, it was great. God I felt so sorry for Prince Charles. I seem to remember at the time William and Harry were being sent to Eton there was a lot of upset behind the scenes as Diana wanted them to go to a day school? I can see how from Charles' perspective sending them to Eton, where Windsor Castle is on the doorstep, was a great kindness.
It did lead to some fascinating trips into Wikipedia to look up some of the minor characters. Dorothy Macmillan, the wife of the PM, did indeed have a long standing affair with Robert Boothby. Her brother, the Duke of Devonshire appears to have been murdered by a Shipman style serial killer GP and it seems as if to avoid too much press attention for Dorothy, the police didn't investigate whether or not there was a murder. WTF.