It sounds like the air temp blend door is stuck in the hot position. Has any one looked at the motor that moves the door? It is probably bad.
It is located under the dash on the HVAC box.
Cheers XXXXX XXXXX help - sorry for taking so long to reply, but after a lot of hard searching I think I may have found the problem, whoever owned the car before me upgraded the engine from a 1300cc to a 1600cc. They also upgraded the dash to the sportka dash. Have also found that one out of the two wires connected to the HCV is not connected to the heater control panel. Will sort out one weekend and get back to you if this solves the problem.