A good friend of mine once confused this with the bear one:

'Does the Pope shit in the woods?' - well i know it's irreverant, but it's still my favourite expression!

'Well, bugger me backwards with a fish fork' - expressing surprise.

'If i laughed once i laughed twice' - bitchy comment when someone makes an unfunny joke.

'I've got nipples like Chapel Hat-pegs' - strike me it's chilly in here today.

I've recently got back in touch with an ex whose whole vocabulary is made up of peculiar sayings so that when we speak no-one else knows what the fuck we're talking about. The sayings wouldn't mean anything to anyone else, but i nearly pee myself everytime he reminds me of one that i'd forgotten!