I desperately want to buy an Audi TT, I looked at one today 1.8tfsi sport 2012 and tomorrow looking at a 2L TD Quattro 2010. I’m on a budget and looking to spend around 7500/8k. Can anyone give any advice to what’s best, what I need to be looking for etc. Help much appreciated. 

Well depending on what kind of driving you do should help you decide whether to go for a diesel or petrol. Diesel better for motorway commutes. Petrol better for short journeys. 

It's all in the service history. Ideally should be full and make sure csmbelts/water pumps have been replaced on time. 

Make sure everything works on the car as parts can be expensive this includes the ac. 

Make sure the gears are smooth as clutches aren't cheap. Same for automatics. 

This YouTube video should help: 

Cheers

Steve

Another thing to look for in these cars is that the drivers and passengers door drop glass is not badly scratched as this can be an indication that the regulator mechanism is going to fail or has been incorrectly set up after replacement.

It's not overly expensive to replace and/or adjust but the glass looks bad when scratched and is quite common, I've seen a few which were like this when I was looking for mine.

When test driving make sure that there is no vibration through the steering wheel at 75-90mph, most folk would suspect that there is a balance issue, however, this is only partially correct. The alloys and tyres can be out of round or flat spotted due to the amount of pot holes in the roads these days. The steering on the TT is also sensitive to tyre types being fitted.

If vibration issues are a problem I'd recommend getting a Hunter Road Force Balance done on the car and an alignment check. The Hunter system is not cheap circa £100 to £200 however, it will pinpoint and correct any issues with the wheels/tyres and stop the vibration when it has been done. A normal full set balance will be in the region of £60 BUT, it may not completely cure the problem, I speak from personal experience.