When I was driving home tonight, I went to use the heater and found that it only worked if turned up to max. even one click below and I was just getting cold air. Everything else seems to be working properly. Fan, air flow direction, air con etc.

Has any body had a similar problem? Any advise?

Mines the other way, can be on full cold and suddenly comes through very hot! I believe from reading other threads that the heater control motors can play up, I think renewing them is only permanent cure.