Their accents are wildly different, which is especially telling in Britain. Not that a nephew and uncle would always have the same economic status, but usually it's not night and day. Not just the accents but the whole gestalt. It'd be like... maybe a more snobbish Anderson Cooper, but with even more money, palling around Italy with a blue-collar young guy from New Jersey who doesn't even know the word for "two" in Italian.
Even with all that, I still didn't see this particular twist coming, nor did a lot of other people, as obvious as "he's gotta be rough trade" might appear in hindsight.