lamona double over fault?

i have a lamona electric double oven and the big bottom oven is not working but the top is fine.
the light on the dile isn't on and the oven doesn't make a noise but the top one does!
could it be a element or the fan that has gone and all power then cuts out or something?
please HELP!!!
thank you!
here is a link to the make and model

http://www.howdens.com/product-range/appliance-collection/ovens/built-under-double-electric/lamona-double-fan-oven/

darren
December 2010