I don’t speak British English, but I (supposedly) teach it.
Maybe part of the reason why I don’t want to continue teaching English in France is because I’m usually expected to teach British English… but I speak American English. The students’ vocabulary books are British English…. but I speak American English. The recordings for the pronunciation labs are in British English… but I speak American English!!!
The students are confused and I’m annoyed at all the vocabulary and pronunciation differences that they can’t pronounce in either accent anyway. Listening to their oral exams make me feel as though I’m talking to several people, first with a Brit who says little with a /t/ and then all of the sudden, the American personality comes out with car with an obvious /r/. They haven’t quite mastered the concept of sticking to one accent. I wish the students had a choice of which accent they wanted to learn though. I wish I could teach nothing but American English since that is what I know best, obviously. I’m afraid the students will constantly confuse the two and accidentally say fanny to a British person and fag to an American thinking of the more innocent meanings or not even knowing the other meanings.
I suppose it was the same when I was learning French in college. We were always taught standard European French even though I preferred Quebecois French. I had to learn how to understand the accent on my own, which isn’t too hard to do with enough listening practice. But knowing more of the common vocabulary differences would have been helpful before I studied at Laval. Luckily I never made the mistake of saying gosses while I was in Quebec, so that’s something at least.