I concur with Big Al Whittle about Pat Walker. He's an extraordinary musician, and can do what he likes.
However, in the 25 plus years I've known him, I don't think I've ever heard him sing (and certainly not speak) with anything approaching a put-on 'Irish' accent.
He does the odd American song in American, which is entirely appropriate. If you try singing American songs in Yorkshire accents, people just laugh.
Whoever this original (Guest) poster was six years ago was, I don't think his ear for accents is that good.