Anyone had a transient problem with their cabin heater? Started the car this morning after it had stood outside all night. Drove about 8 miles before I realised that the heater was very hot. Turned all heater controls off so no lights were illuminated on the facia; even turned the temperature to cold. Still really hot air was coming into the car and would not stop! Pulled in to a lay-by, turned ignition, off waited 5 minutes, re-started and everything had righted. No further problems therafter!