I finally got round to changing the fuel filter, simple 15 - 20 minute job. Cranked the engine for 20-25 seconds and she was purring like a kitten. The hardest part of it was paying for the filter, £49 from Derby Audi!!! Even the parts guy winced at that, lol. Even so it was way cheaper than a main stealer service, i was quoted £469 with optional fuel filter and brake fluid change.
I did the lot, including ALL filters (genuine parts + 8.2 litres!! of castrol edge, which i'm led to beleive main dealers don't use) for £156 + around 1 1/2 hours of my time.
I know if i ever sell it, some people will be put off by the lack of full main dealer or specialist service history but i know all the filters have been changed and the work done properly and at a fraction of the cost.