Hi mate, yes it was indeed the inlet manifold flap, the garage changed both the flap motor and the wiring to it, apparently both the motor and wiring is a common fault. He also put a fuel treatment in, that addresses clogged up turbos and egr valves. Drives like new now! and it has 120k on the clock.
I had it retro-fitted for me. I'm all thumbs when it comes to car wiring and electricals so I didn't even consider trying it myself.
S8craig - one of the members on here did it for me: http://www.tclsatnav.com/
Did you retro-fit your DVD Sat Nav into your car or was it factory fitted? I have an 04 A6 and am considering buying the Audi RNS-D parts to retro-fit and was just wondering if you knew whether its just a matter of plug and play?