I just did this tonight on my oven.
I held one of the blades with mole grips and then used socket wrench on the centre nut.
Its a left hand thread so turn it to the right to undo it.
Once the nutwas off, I got the old grips on the fan boss and wigged it about to get it free. I had to use some wd40 to free it.
What a stupid design to put that screw behind the fan though!
Now I am looking for someone to supply the element
Martin
November 2009