I've got the same problem.
Grill works but oven doesn't.
This means that thermostat should be fine, I think it's the selector knob.
My oven has 5 options on the selector knob; all others are fine apart from the fan-oven's. I'll try to move the wires around so that selecting the Fan-only function would switch the oven on - we've never used the Fan-only function.
doctorincambridge, August 2010