Other mistake: The documents to which the Imperial Seal was stamped at both the coronations in Peking (1908) and 'puppet' coronation in Manchuria (1934) carry the same dates. They also show the same 'coronation names' when it is known that Puyi was coronated as 'Xuantong' in Peking and 'Kangde' in Manchuria. This will only be apparent if one can read Chinese. (00:14:45 - 01:47:40)
Other mistake: Ritchie's 1950's Fender guitar amp looks like it would have looked in the 1980's when it should have only been a couple of years old in the movie.
Other mistake: A tracking shot along the street in East London, South Africa, where Dame Penelope Wilton drops Kevin Kline off, shows the Midlands Hotel and Boggie's Clock, two landmarks in Gweru, Zimbabwe, and therefore not in South Africa.