OK, update!
Car is with VW Huddersfield today for an air conditioning service. The service was carried out but after this they found it was still not working and that is was the compressor that had gone. As my car is an 06 is it out of warranty, however VW have offered to pay for 100% of the cost of parts, and 50% of the labour costs. So it's costing me £168, plus the £75 service fee.
I'm guessing they have had lots of problems with compressors?