Rayburn too hot

I have a Rayburn Supreme solid fuel. No matter how much I try to set the controls it burns much too hot. I have checked the thermostat damper is not clogged and is working properly, I can’t see where else it could be drawing air in. I had a concrete flue liner a couple of years ago, I am wondering if the flue diameter could cause this problem. Any advice would be very much appreciated.

Try closing the flue damper a bit more , also ash pit door air screw.
Are the doors sealing correctly?

Hi Terry, the doors seem to fit OK, I had the flue damper slide open about 3 Inches, I have moved it to about 1 inch now, should I leave the flue damper door open, or should I close it? It is not lit at the moment as the weather is quite warm, but hopefully with the damper slide closed up a bit, it will not get so hot.
Thanks for your help mate.