If the fan isn't working the circular heating element around it wont work or will cut out on overheat.
You need to find out if the fan has power getting to it. If so then it is fair to assume its kaput.
Go to: www.espares.co.uk click on spares for your cooker and see if they stock your fan. Then click on their Advice Centre and they will have a U-tube video of how to replace the fan
GB in Wales, February 2013