No problem.
Just a little update, post flush. We’re away this weekend, so have put 150mi solid drive since the flush.
The car is now much hotter. Still nowhere near where my wife’s GLA gets, but I wasn’t cold on the drive.
@Redwolf do you have Carista by chance? I do, and found a HVAC calibration which checked and set all the flaps on the vents. That would (I think) throw an error is any we’re stuck. Don’t know if that helps or not.