Bosch HBN70 keeps tripping the RCCB when temperature is reached?

hi, we have a Bosch HBN70 double oven which trips out the downstairs circuit breaker (RCD/RCCB) when using the lower oven, it only happens when it reaches the temperature and the heater is supposed to cut out.

after it trips out, we reset the RCD, and the oven can trip out up to 5 more times before eventually working as normal.

do we need an electrician, a bosch engineer, or could I fix the problem myself?

any advice / suggestions would be appreciated.

p.s. this has only started since the oven light went out - could that be connected?

thanks

steeephen
September 2008