One must understand: this film was made in America, early during the war (filmed between November 1941-April 1942, according to this website). It was filmed on an MGM sound stage in Los Angeles, California. To fault it for a lack of authentic architecture or accents is like attacking a performance of a Shakespeare play because the text contains anachronisms or the set isn't sufficiently realistic.
It's funny how some criticize the movie for not showing enough deprivation on the part of the British, at the same time they accuse it of being mere propaganda. If it was mere propaganda, then it would have exaggerated the travails of the British, not underplayed them.
Nevertheless, of course it was propaganda. But that doesn't mean it can't be great art. Or do you attack Picasso's Guernica, Shakespeare's Richard III, or the Chartres Cathedral because they were propaganda?

Just watched this film. Read a lot of good reports. Was looking forward to it. Knowing the subsequent real life of Greer Garson and Richard Ney shone a strange light on their interplay.
Good story with a sad, sad ending. Good directing and sets. Characterisation could have been better (thinking of Garson and Ney). Overall perhaps slightly overrated.
7/10