A/C diagnostic specialist

Hello,

I've got a persistent leak in my A/C system (Octavia 2 - pre F/L) which my regular garage say they can't diagnose as it needs to go to a specialist who'll do the nitrogen/UV dye test.

Has anybody here used a decent auto A/C specialist in the SW Surrey/N Hants area who I might also be able to consult?

Many thanks in advance,

David.