Disco 2 2000 Td5 Aircon problem

My Aircon has a problem, it's stopped blowing nice and cold. It had been on a long time in hot sunny weather for over 400 miles continuous driving. Anybody have advice on where I should start to work out what the problem is. Seemed to get a stream of visible gas/vapour (?) come through the central drivers side vent only and stopped if I switched the climate control off but came back when switched back on. This felt cold but couldn't smell anything and it stopped after a while but air was not now being effectively cooled.

if you have a low gas/gas leak the dual pressure switch will stop the compressor clutch to engage and no cooling...first step is to rule out a leak and make sure it has enough gas pressure

stupid question sierrafery, but how do I check that?

you dont, go to those who are doing this dor a living

cheers!