Young Burgess - U.S. Army insructional video.
With hindsight it seems like a parody. But a decent guide for the time.
A great actor and a gentleman.
I came to post this same video. WW2 Training Film for US Soldiers | How to Behave in Britain | 1943
It's pretty good, worth a watch, especially when the "Yank" bounds into the British pub making his mouth go.
Then Burgess shows how it's done like a true gentleman.
Those of us who know vintage British automobiles know the reason why the British drink warm beer is because Lucas makes the refrigerators..