Thanks for that, most French workmen don't seem to know the regs regarding anything either so you're not alone there :D
I think on further inspection it's because the fan and thermostat had gone that excess 'vapour' from the oven was venting out the fan inlet when it was overheating...
Old one just croaked on us so I've whipped the beast out of the 'carcass' it was installed in. My question is if an oven has a vent (it was a fan assisted electric one) on the back as this seems to, should it either have an airspace behind it when installed or should it be vented to outside? I...