Any Aircon Gurus??

Hi All.... not posted in quite a while so posting in a couple of area's as platforms are similar , recently acquired an A5 Quattro black edition + and when i got it around 4 months ago the aircon wasn't working , it was totally empty wouldn't even let the button light up there are no signs of any accident damage or reasons the front end may have been stripped down so i took it to a local independent and he pulled a vacuum on it which it held and then he re gassed it and added some dye just in case i was to return and it's been icy cold ever since until this week where it has clearly got issues , the aircon button still works , it switches the compressor on and off and as far as i can tell there are no leaks though i have yet to take the under tray off , when i attach a gauge to the low pressure it reads high and then when i start the engine it drops down into the green zone which as far as i know is good , are there any fuses , sensors or relays I can test before i got and try another re gas ? i've had it on VCDS and that reports no faults and iv'r gone through all the output test which seems to work , im baffled

Ok so I have VCDS and ran all the diagnostic output checks ....the only one I saw that showed any kind of preasure read 7 psi but i don't know where I should be looking
I dont hear the cooling fans kicking in any time but i wouldn't have thought this would matter when driving motorway speeds again maybe im wrong i know zero about aircon

It's a strange one , Ive bought a UV torch to check for any leaks and Ive removed the glovebox to check all the flap motors are working which they seem to be , pollen filter is clean and ive bought a can of gas to give it a boost , if the gas fixes it then clearly there's a leak somewhere ,,, ill keep ya posted when it all arrives