I've quickly run DIS now, but no faults were logged with the IHKA module or anything else that would affect the A/C.

I activated the electric fan through DIS and it came on immediately.

I displayed all the A/C control values and couldn't see any odd ones.
Temps were all good, and as soon as I hit the A/C button, it showed up as active and the compressor began spinning at 600/700 rpm.

Hmmm, will have to interogate the displayed values a bit more I think.
Only had a quick look, so maybe there is more to see there - I hope!

Any ideas more than welcome.