Here's a dictionary of slang as used in various parts of what is colloquially referred to as the UK.

I'd put more faith in this than the OED on this kind of thing. But the real reasons I put the link in is because I though people might enjoy browsing it. Ballocks is fine by me - so long as it's pronounced with a short o in the first syllable. (ie not to rhyme with Warlocks and forelocks.)

Talking (more or less) of which, I always think it was sad that the Bolick Brothers felt they had to use the professional name The Blue Sky Boys, no doubt because they rightly anticipated a tricky time if they stuck with their own family name.