There is a bleed screw directly on top of the thermostat housing. Open that while the car is running with an 8mm spanner (just loose not all the way out) and it should fizz while air comes out then after a while just coolant. Retighten then test to see if it runs to temperature ok.
There may be another bleed screw somewhere but this is the only one I know. I hope that helps.
J.