I would suggest that a local VW specialist or a air con engineer would be able to fix this cheaper than the stealer!
My climatronic system blows semi cold air out when on the lowest setting so I need to get my system re-gassed, VW wanted ?105 and a local re-fridgeration engineer would do it for about ?45.
The difference between the 2 is that VW will empty all the gas and dispose of it, where as the other guys will just top up the system.
HTH