I have the balance of a two year lease on a 2008 Audi Avant 2.0 TDI. Unfortunately the particulate filter light comes on at relatively short intervals - variously 180 to 350 miles, which is very inconvenient (as no doubt you are aware means constant 2,500 rpm for 5-7 miles to clear). If ignored, after only a few miles it goes to "limp home mode" and subsequently Audi assist. My motorway use is minimal, but I cannot accept this as a condition of satisfactory ownership. Whenever convenient, maybe 70%, I use superior diesel. I cannot be certain whether this helps or not, but fuel consumption is improved, as you have rightly claimed often in your column. The car has now covered just over 9,000 miles and was serviced last week as advised by the in car computer. The dealer claims to have carried out all tests and advises that nothing more can be done to resolve this problem, which he did have the good grace to acknowledge was a known problem, further confirmed by Audi assist. Suffice to say the salesman did not warn me about this problem. I would very much appreciate your observations on this matter. Should I return the car as unsuitable for use? is it too late having put up with it until the first service? Or do I accept the problem and get out of the contract asap.