No AC

[ScottD3]

The AC was never very cold on the A8 since I bought it and I've always put it down to the lack of gas.
I dropped the car off to Audi for a AC Service.
Picked it up and it was cold, drove home and was the same.
The weather was it as hit as it has been so I waited till it was really hot.
Spent the day in Bristol and basically the AC the ****e. Pumping out warm air and not cooling at all.

Got home and phoned Audi.
They basically said it tested fine but it's in for a AC service not fault finding, so they just gas it up, do the other bits and ship it off.
If it's not working I can drop it in for a diagnostic session at £50.
Sod that, I went off to talk to a AC chap I know.I have no idea why I never seen him first.
He suggested I replace the pressure switch first.
So I did, no difference.

When I put vcds on the A4 I could see what's going on with the AC system but for some reason vcds does not have a label for HVAC system for the 8.

Does anyone know what each message block does in vcds or another way to test the AC system?

I has gas, I'm thinking it's the pump that's gone now.