Thanks people - waiting for keys to arrive from merc, ordered via log book - I just hope the barrel hasn't been changed during its life - not too bothered about doors, can change these ok, but don't want to dismantle the entire column and drill off lock etc. I am never, ever going to procrastinate about buying that 2nd set again!

I might nip down the boneyard and see if I can borrow a fistful of old keys, you never know your luck - any cabstars I'll try first.