Grinner
Not fat gutted. Hirsuteness of shoulders TBD.
Weirdly - and generally speaking - the Irish aren't great at doing English accents, and the English not great at doing Irish ...This is possibly because we both get quite worked up when it's done wrong. The Scots & Welsh though, usually get the estuary accent down to a tee...Sean Connery not permitting, who just clearly never bothered to do anything, even when playing roles that obviously called for it.
American is much easier for all Brits because it's a) something everyone has culturally grown up with, and b) there aren't as many specific dialects that get as scrutinised. General miscellaneous American will do fine. I've blagged it as an American in America and not got found out till I got really drunk by just saying I've moved around a bit (I've also done Irish in Ireland, and got clocked instantly, and then had to have a long, grovelling conversation where I had to reassure them I really, honestly, wasn't taking the piss)...Doing a specific New York or Boston accent will be much harder. But few really bother with it.
What sort of weirdo bowls around the US doing a yank accent? I purposefully retain my British accent because people think I'm dead clever and it gets the yank birds foaming at the gash.