Hot air doesn't blow when aircon is on

[RockDriver]

Some weird behavior on my E70. Now that the weather is getting colder, I tried to turn up the temperature, but if the aircon is on, I can set the temperature to max and the vents are still blowing cold air. If I turn the aircon off, then it starts blowing hot air, but at the same time windows go full on misty which is annoying as hell. I've fiddled with the iDrive and set the temps to max there too, but no change.

Any idea what could be broken here? Also any recommended places in London that could diagnose this would be appreciated.