Im in Bournemouth, so if anyone could recommend a good one reasonably close by that would be great!
VAS works - Holton Heath
Kartechnic - Nuffield Industrial Estate
Used VAS works for a Revo, and Kartechnic for an immobiliser recode. A colleague has had good service from Kartechnic.
To be honest, if it's just an oil change service / routine stuff and I didn't want to do it myself I'd use any garage with a decent reputation and supply the consumables myself. Simple bread and butter work.
As for the handbrake issue, it's probably more likely to be a wiring glitch (failed switch in the lever?) than a software issue, and I can't think I'd be able to see much on VAGCOM so would expect similar with a proper VW tool. Probably a multimeter job.
As for sourcing consumables, being in B'mouth you might be interested to know that you can get access to the local TPS if you join a local club for a fiver. They won't serve cash buyers unless you're a club member.