Replacing main oven thermostat in Smeg A42-5

Unbelievable. 3 weeks before I move house and the thermostat has gone (oven goes to top temperature no matter what the setting). I can’t find any documents showing what needs to be removed to be able to replace it. Does the hob need to be taken off or is it accesible from the back of the oven ? If its an easy job I’d rather pay £40 for the part than £130+ for a fixed price repair. Thanks for any advice.