It will be the reostat (heater resistor pack)... always prone to go at this time of year with the change of weather / temperature.
The GF's is doing the same thing now the only thing you can control is the temperature and direction of air
A new reostat is very expensive... Around £200 and a dealer part only!
You can repair them if you know what you are doing though
Thanks. Garage just called. £211 to fit a new one!! The part alone is £120!! Ridiculous!
Thanks for help guys much appreciated!!