The problem is the element at the rear which sits around the fan It is shaped in the form of a ring and is generally about 7-9 inches in diameter. It has a small fixing plate screwed or bolted to the rear of of the inside of the oven to the left hand side of the fan. To reach it you have to take off the backplate at the rear of the inside of the oven ( four screws ). When you extract the element you will see that it has burst at some point on the ring itself. Make sure that you fit the correct one for that oven. There are many sellers on Ebay.
John Livewire, August 2010