Hmmmm...I haven't watched that episode in a while. What accent is it specifically? I can recognize Sheffield, because I had a friend as a kid who was from Sheffield, and I can distinguish between RP, and your general Northern and Southern English accents, and Welsh, and of course Scots and Irish accents, but beyond those basic distinctions I'm not great... Well, actually, I think that's very good for an American! I'm at least as good as I am with the various American accents.
Oh, I'll just have to watch the episode again. That way, when I picture you as a vague mixture of Ewan McGregor, David Tennant, Clive Owen and Danger Mouse, I'll know exactly which accent to give you.