We have a zanussi double oven ZOD 350X and the main fan oven is not reaching/holding the correct temperature. I've changed the element and also the thermostat but it's still the same. I'm not 100% sure that the fan is working properly but didn't think that would stop the oven reaching temperature, am I wrong on that? Any suggestions would be appreciated as we don't want to replace anything else until we know for sure. Thanks