
There are a multitude of things you can do to continue investigating the car but the previous comment still applies and you may expend more cash to arrive at the same outcome

For that reason get the car along to one of the specialist garages (eg: AMD, QST etc etc) or Audi for a complete check as it will be £200-300 well spent if you still remain committed to buying this car AND one final item might be to get the garage to contribute to the price of a quality warranty (eg: Warrany Direct or Audi etc etc) rather than their purchased warranty.
Having said all that "if you are in any way uncertain, simply walk away"...sorry to bore you
Hope that helps. Good luck
