Aircon works but not on full... help

[caveman121983]

Ok little back story, i bought a 2005 Vauxhall Astra Mk5 1.9 CDTI, the air con didnt work when i got it and after doing some repairs i noticed the condenser was damaged so i bought a new one fitted it then took it to the garage to be regassed. They have a policy of Charge or no charge so if it doesnt work you dont get charged.

they charged it up no leaks everything ok but i wasnt charged because it wasnt getting colder.
I after some playing found out that it was in fact WAS working but only when the Fan speed was on 1-6 NOT 7 which the guarage had automatically put it on for testing.
now my car has climate control so its all digital. i do have a VAUXCOM adaptor so i can interface with the OBC and ECU and see the aircon pressure and status of if air con is on or not.

sure enough as soon as i turn the blower to full the air con switches off but the in car selector to turn it on or off shows its on.

Does anybody have any idea what could cause my aircon to turn off when fan is on full?
any info or direction would be appriciated