To my shame,'I'd never heard of rhotic/non-rhotic accents, until hanging out on here.
DH is Irish, but they moved to England when he was about 14 or 15. He had the pissed ripped out of his accent, and so (sadly) lost it quite quickly and now has a generic BBC accent.
Except, that there's the odd word he still says, and there's a hint of an 'r' buried down there. 💚