Any ideas what is the fault?

No it is the element that will either be working or not working. An element can't be partly broken. The thermostat on the other hand can do both. Work or not work and also work but not regulate properly. They can definitely turn off the element before reaching the correct temperature if they are faulty.

Lincoln Appliance NZ
August 2017

It's Definitely the fan oven..turned oven on again to check.so the Fan is spinning ok and there is warm air coming from it almost immediately. So would that indicate that the element is fine or could it be partially broken and not producing maximum heat ? So I should probably start with changing the thermostat then ? I thought a thermostat should be either working or not working... So it's possibly jus not working properly ? Thanks

Gary
August 2017

More info from a Google search (that you could have done)

https://www.justanswer.com/uk-appliance/6g0k4-temperature-rangemaster-classic-90-not-heating.html

Acp
August 2017

May be the thermostat however, are you sure you are looking at the fan oven, not conventional?

See this response:

https://www.justanswer.com/uk-appliance/7rgvc-hi-electric-rangemaster-110-main-oven-works-does-not.html

Acp
August 2017