I also had this problem once just last week, (heaters) I have a 1.4 though mate. It was really icey/frosty and this has never happened before or again since but one morning travelling to work i drove roughly 5 miles if that, heating was at 90degrees normal and no heat comming out mate. Thought it was maybe down to being about -10, -15 degress throughout the night and early morning. Not sure though... Like i said it hasnt happened again. Can anyone shed some light on this?
(Sorry if this is hi-jacking ur thread)