UPdate:
I took the car to a dealer and was told straight away that the fan wasn't working at full speed.

The car needs a new thermostat, Fan Coupling and a new fan Blade.

Was told it would take 3hrs to fix, is this correct? as labour charge here in the uk is £100 p/h.
The strange thing is the car heater still worked blowing hot air out and the temp gauge never went past half.

I did try and get rid of the air lock but that didn't help with my problem. I hope i havent caused any major damage to the head gasket(checked it and no water in the engine oil)