Here are my comments. The parentheses indicate that something is not part of General American-like dialects or RP, but is found in certain regional dialects..
CAR ------ American R's are always pronounced, British R's are not.
In General American vs. RP, yes, (but there are non-rhotic American dialects on the East coast, and rhotic British dialects.)
NO -------- British is /əʊ/, American is /oʊ/
Some British dialects have /o/. Some American dialects have /o/. (Some American dialects have /əʊ/.)
NOT ------ British is /ɒ/, American is /ɑ/
Actually in about 40% of the country "not" can have /ɒ/ or /ɑ/ used interchangeably.
NOT ------ British final T's are released, American final T's are not.
yeah
LAW ----- In BrE it's /o/, in AmE it's either /ɒ/ or /ɑ/
Actually I belive RP has /O:/ rather than /o/. (In the Boston Brahmin accent it can also be /O:/)
CLASS --- Some vowels that are /ɑ/ in BrE, in AmE are /æ/
Some people in the West can shift /æ/ to /a/. (Some dialects in Boston have a similar trap-bath split.)
BETTY --- In BrE there are no tapped T's, in AmE there are.
From what I've heard, occasionally BrE speakers use tapped t's.
NOW ----- In BrE it's more like /ɑʊ/, in AmE it's more like /æʊ/
Actually General American has /aʊ/. Some regional dialects have /æʊ/.