Thanks sorry my terminology and limited knowledge! The oven is on a 13amp plug. It’s on what appears to be shared with the kitchen sockets including the appliances.
Its labelled rcbo has a test switch on top which if you press flicks it over. We’ve had the washing machine, toaster, kettle all running on the same circuit at the same time with no problems.
The turbo grill which I think is the top element and the fan works fine it just trips shortly after switching the oven (as in top and bottom elements on).
cheers
oh and for info it was Hotpoint protect and repair that recommended this site.