I looked on the Audi website for all the dealers near where I lived and where I worked. I then emailed the various garages for a quote and a breakdown of the work.
That way you have written confirmation of the price from them. I went with Southampton Audi when I phoned up to book my car in the price of the service was £15 more thna I had been quoted in the email but when I told him what I had been quoted he never questioned it.
Sure, get a quote and also ask their hourly rate and oil prices. Enter those in the Audi service price spreadsheet (service spreadsheet) and see whet you get. If their quote is better then good for you, get it in writing.
If its over the price ask them why they are charging more than audi recommends and would they mind if you told Audi UK about their practice?