Every day a school day.
I've learned some stuff here and I hope I've helped to pass it on too, which presumably is what the A8 parts forum is all about.
Thanks to all you chaps who posted on here in the most genuine and helpful manner.
My car is purring like a kitten.
I am, on the other hand, quite mightily pi$$ed off.
My letter to Audi will be sent later on today. I'll be looking for a 100% refund of the labour at the very least.
Edit to add: Conan! Correctamundo! Your post #2 was right on the money.
I'm impressed. :-)