Had my cambelt changed, full service and a new rear caliper fitted for £498.00. I had done 54k but my car is 8 years old.
The garage told me audi are the only manufacturers not to specify definite miles or cmabelt age before replacement. They just quote 'inspect', and to 'inspect' takes a whole lot of work anyway. But I feel your better of sticking to a standard 60k or 80k depending on your engine.
What really hurt was the mechanic told me the car had previously had the cambelt changed, but I was unaware of this as there wasn't any note in the service history and no reciepts. Ba$^@rd previous owners could have been a bit more thoughtfull - I had to shell out for a new cambelt and it wasn't even needed!!!