The problem has been ongoing for a month & we cannot use the oven. We removed all the elements & checked the resistance & they were fine. We also checked the resistance of the oven thermostat & that was also fine. We then ordered a new tangential cooling fan as well as a cooling fan thermostat & replaced that. Unfortunately it’s still not working. The moment the oven reaches about 140/150 degrees, it shuts down completely. Even the clock goes dead. After about 15 minutes, we can switch it back on again. Although we’ve replaced the cooling fan, the cooling fan doesn’t actually switch on. The oven doesn’t trip anything, it simply switches itself off. We replaced the cooling fan because after doing lots of googling it seemed like the most plausible problem. We had hoped that the fan’s motor had packed up & that by replacing it, the problem would be resolved. Does the fan maybe have a controller that could be broken? Thank you for the feedback.