This morning whilst warming up the car @ -9 deg c on a short test drive.
The car started blowing Baltic cold air into the footwell, it made my feet go numb. The top vents were still warm.
It appears as if it had spit a 6" by 1" bit of plastic out from the centre console behind the pedal box.
I guess the main air intake pre heater matrix is here, the air was freezing & bellowing out. I managed to gaffer tape the part back into place to make the car drivable without suffering frost bite.
New part ordered £11.65 , it a 100 mile round trip for a warranty claim
Hope nothing else fails, the radio LCD display is getting slow to respond as the temp drops