Brought a 30 day old ex-demo sportback TDI S-line about 1.5 months ago. It had a knocking noise from the rear and noticed this 2 days after buying the car. I went into audi and informed them of this problem. I booked the car in for repair and it took them 3.5 weeks because they didnt have any loan cars to give me. My car is now in audi and they have had it for over a week now trying to fix the knocking noise. They can hear it but cant find it or fix it. They have now filed a report to AUdi HQ in germany. Where do I stand with this. The service engineer worried me today saying Audi might sugguest returning the car to the customer with repair... What can I demand and what are my rights?