Iíve decided that after 4 years away from Audi ownership (I previously had a 2006 A4 Tfsi Q SLine SE with a remap), the time is right to return. My circumstances are such that I can now afford an A6. I really like the Black editions and have a budget of Iíd guess around £22k at the most. That means that Iím probably looking at around a 13-64plate with under 40k miles. Prefer saloon but not ruling out avant.
Around 9-10k trade in and Iíll borrow the remainder. It may well be later in the year before I eventually buy one but right now Iím at the stage where Iím reading everything I can on each model, and watching and reading reviews etc.
I obviously have a few questions.

I fancy the 3.0Tdi engine but donít need the power for anything other than vanity. I wonít be towing and the car wonít be loaded. Is the 3.0Tdi worth the extra outlay in purchase and in running costs? How much extra?
Iíve seen one or two cars with what looks like air condition controls on the centre console for the rear, but not on others. What is that?

Running costs. My annual mileage is around 8-9k miles so running costs wonít be huge. Is the service interval every 20k? Or 12 months?

Excluding any finance/debt payments, I could spend as much as £300 per month on running costs for fuel, service, insurance etc. My guess is that this will be plenty (insurance is around £300 for 3.0tdi for me)

And finally.....are there any good indy garages in Hamilton/Lanarkshire area so I can avoid dealer prices??

Apologies for the barrage of questions to start but I appreciate any advice and answers you can give.