Dunno why, but I edited my post again before and its gone? Anyway, I reckon the pipe on the bottom diagram above is too different. Looks like the bore is smaller as its for a TZI not a GTI. Other component numbers are different too.
Bloody hell if kwik-fit charged £87.50 in 1985 itd be about £300 now! If they even sell them still... Will call in tomorrow and find out - there's one on my way to work. Cheers

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I'm straying towards removing it and sticking a piece of straight pipe in instead. I'd be a lot more confident of that lasting than patching up the old one. The repair to it as is just seems to consist of lathering the front of it in gun-gum. Until I chip it all away then I won't know how bad it is. Can't risk doing that until I've got a definite fix though.
Will double check the part number with car parts warehouse tomorrow, but if removing it altogether is an option I'd much rather do that. In all honesty its really not noisy now - I can't imagine it'd be any worse with the silencer out and a pipe in its place. Opinions?
Cheers,
Matt.