The speed resistor for the fan gets hot they always have,but yrs ago they were located outside the cabin area(open to the atmosphere),where as now they're located in the airflow of the fan..relocate it back outside(problem solved)
Just been watching the parliamentary select committee looking into this issue. GM did not come across well and there is no convincing evidence the issue is over. Vauxhall have 5 cars with current recalls for fire issues!