Hi Martin,
I got a slightly lower price at £220 from an independent garage for the spark plugs. And in the end i decided to do this myself (£50 for plugs and 1.5 hours of my time which i could have done it in 30 minutes TBH). Which some say i am crazy to do whilst my car is still under warranty, but i'd like to think i'd take more care (I am a little OCD), and hey, it's been going fine for the last 2k miles.
Some not so great pictures if you wanted to do yourself.
I agree with Gareth, do you air filter as well. You can do this for £10 for the filter and 30 minutes of your time. Again, i've done this myself twice already. Crazy that Audi recommend for me to change the air filter every 60k miles.
Thanks, Joe