80k miles with a single fuel filter? Wow you really got clean fuels
Get a good quality fuel filter and change it asap - it's cheap compared to all you have done and the change is real easy. If it's not the filter, it's value added for the operation of your audi. 80k miles with one filter... wow. Not sure what kind of marketing the audi long-life servicing is. I change filters every 10-15k km, including the petrol filter, disregarding the fact I'm on LPG. I use only VW spec or better filters, you just can't compromise with these, they are consumable anyway.