Cheers Shaun

No it doesn't have any of that, not sure what was going on with the advert there! Yeah compared to the Golf it's gutless but performance seems fine when it's not in limp mode and the turbo seems to spool up ok. Brakes are good and suspension all seems ok. Performance wise it feels the same as others I have driven (one Passat I drove had exactly the same limp mode symptoms).
That's the thing really, I think it's probably best to walk away but I've got this niggling feeling it may be something dead simple in which case it would be a good cheap buy. It's the tidiest I've seen and all the cars in my budget are around 150k-222k but the others have no paperwork to back up parts, let alone a full Audi service history.
You are dead right about issues that could arise however I think that will be the case with whatever I buy, I'm viewing this as disposable motoring really. Tricky one.