I realise this is too late for Richard, but we have had to replace the fan element on our Siemens HB 903 oven four or five times over the last eight years - at an average cost of over £100 !! Customer liaison for Siemens/BSH Appliances were simply not interested once the guarantee period was up. The last time the fan element blew (this week), the repair man couldn't undo one of the screws, but he was still able to replace the element by moving the oven out into the room and doing it from the back. It cost me £167 this time (£68 for the part and £100 for the labour).
The repair man saids don't ever use WD-40 - as it takes ages to get rid of the smell!
Needless to say, I won't be buying a Siemens oven ever again.
John
November 2011