Can I fix Baumatic- blows circuit when using grill or convector oven?

Hi
My Baumatic fan oven stopped working, although the fan worked it didn't heat up. I switched to using the convector oven instead as we were planning to replace kitchen in a few years. Now the convector oven blows the circuit if you switch it on. The grill also blows the circuit. From previous answers I think it probably needs both elements replacing. We've had a quote for £200, does this seem expensive- the parts only add up to about £50.