My 1993 200 TDI air con system is not as cold as it once was, up until this year it was sometimes necessary to turn the cooling down it was that good, seems it may need a recharge. There's no record of this being done before I bought her and I've not had it recharged since purchase in 2003. I've checked the labelling on the compressor and it says refill with R12 which I know you can't get these days and I know I can't recharge with one of those Halfords kits as they are R134A. Is it possible to get this system converted and charged with R134A the same as I did with the R12 system on my 1985 Jaguar where the engineer only replaced the charging ports, drier, oil and gas?