Good place near Reading/Henley/Marlow to get air con fixed

[theador]

My air con isn't working, apparently it has a blockage, the low pressure side is too high on pressure.

It's a retro fitted Sanden system on a 1994 Volvo 850. The garage I took it to to get gassed recon they'll just be too expensive for an old car.

Anyone know any good cheap garages for air con in the Henley/Reading/Marlow/Maidenhead Area?