I'd say that "taught" and "taut" rhyme with "sport", whereas "tot" rhymes with "spot"
Definitely. I find it fascinating how pronunciations can change so much geographically and the UK certainly has some variety in that regard.
I remember being a kid on a German school exchange and being surprised that they couldn't distinguish between "salary" and "celery". I've also heard that Germans find it almost impossible to pronounce "squirrel".
I also had difficulty on a holiday to the U.S. and trying to ask someone in a shop where the "batteries" were. He just couldn't understand me until I described them and he said "Oh! Badderies". My wife also had a problem asking for "Winston's" cigarettes until the lady at the counter exclaimed "Wenston's"