Even for foreigners such as myself, who have lived for an extended period in the British Isles, it’s very difficult to distinguish one accent from another. The UK, despite being pretty tiny, seems to have more variation in dialect than the whole of the gigantic United States. I would often find myself struggling to tell if an accent was Northern or Scottish, Irish or Scottish, Cockney or Western.
As an American, I can’t even replicate the accents properly, so if I tried to ask for help distinguishing an accent from a British friend later, the best I could hope would be that I’d sound sort of like Stewie Griffin, and nothing like the accent I’d heard.
Fortunately, dialect coach Andrew Jack has the sounds and cadences of the many British accents figured out, and can give you a quick rundown of each.