Update:

Thank you hoi polloi!

New RCV fitted today.

Now as the compressor counts up to 0.820 the compressor load also counts up, and vent temp immediately counts down until it’s below 6deg. Adjust the temp dial and the compressor current varies down with the load and vent temp matching.

All the AC experts said I need a new compressor, drier and TX valve, now thinking back I bet our old mk5 only needed a valve when I paid 1500 for the 3 items...