Top right hand side (behind the control panel door) at the top you should see a data badge with the model No. and the important GC number, however if you have had a modified control panel and wiring loom kit fitted the numpty that fitted it may not have written the relevent data on the new data plate that comes with the new PCB kit in which case you are going to have to identify which boiler you have
I think there are two fans, one used in the 30 - 100L and a separate fan used in the largest 120L
If your house is 4 bed or less i would guess at the Suprima 30-100 Fan
www.elanar.co.uk
November 2009