The one with Jimmy Edwards and Laurence Harvey? Too late! I saw it a year or two ago. I agree with you, though, it doesn't do the book justice at all. It doesn't even seem to resemble the book a lot of the time!
Helpfully a Bummel was explained (in a quote from the book) on the back cover of the edition I've just read so I was fully conversant with its meaning from the off
I suppose he had the (supposed) lack of a sense of humour/strict adherence to authority in your typical German summed up pretty well, if not the stuff in that closing chapter! I liked his rant about certain authors' over-reliance on florid descriptions of the scenery in their books too. That's one of the things that always put me off Thomas Hardy (after reading Far From The Madding Crowd).
Cheers for the tips on his other books too, Geffs. I'm quite the novice on Mr Jerome so that's all very handy.