Minor problem I admit but has anyone got any ideas why my 8 year old fan oven has suddenly started eating bulbs like crazy. Costing me a fortune. Standard 15w ses high temp bulb, cover and seals all intact. Oven plugged into standard sso on 32A radial with nothing else on circuit. Original bulb lasted about 4 years. Recently had 4 bulbs in 5 months. Is it just a coincidence of me getting dodgy bulbs (tried different makes - Osram, GE, Tesco) or are sinister powers at work here.