Air con has never worked on my occy, put one of those DIY air con regassing jobbies and I could hear it all **** back out. Seemed to be around the compressor area. 

Took it to euromaster to diagnose and it was leaking so bad they couldn't put the uv dye/gas mixture in!

 

Has anyone experienced this? And know what's best to replace/look for before I start spraying everything with soapy water and waste more gas.. 

It sounds like your compressor has failed unfortunately. All too common I'm afraid. Although I thought they broke up internally I've never heard of them leaking that bad. If it's broke up inside you'll also need to have the whole system flushed out and a new condenser fitted too which involves the front bumper to be removed. It is possible to do it yourself as they'll be no need to drain the gas out by the sound of it. However, allow 4 to 5 hours to do it as it's a lot of work. Unfortunately, it's going to cost a bit of money even doing it yourself. At least £150 - £200 for the compressor and a cheap condenser will be at least £100.

Don't keep adding gas as it'll just escape.

 

Take it to a proper AC specialist and see if they can find the hole.