Check JKM's prices, they're posted on they're website
http://www.jkm.org.uk/performance/service.htmI've used them for a number of years and wouldn't go anywhere else. I even took my brand new Leon FR there rather than the dealers.
Subjectively it's not just about cost. JKM's standard of service is beyond that of any other service agent I've used, even main dealers. Even with non VAG group cars I've taken there. I would pay whatever their rate is regardless.
As it happens they are competitive and so a good benchmark for charges I think.
I cannot overstate how good they are, and you probably wouldn't believe me!