I did not get an answer from here....
However had a chat with a local break down guy who had this before......... The owner of the house previous to me had swapped out the oven bulb with a standard one you can pick up from screwfix instead of NEFF`s own slow blow lamps.
The result being when it popped it blew the main pcb board! You could replace it, costly though and there is no way of telling it hasn`t blown the control board too ( until you have spent money on the pcb)
Outcome ..... I bought a new Bosch Oven to replace it unfortunately, We have only been in the house 12 months and at a guess it would be 5 years old so decided not worth it.
Sold the NEFF parts on ebay.
Hope that helps ( not how you hoped I guess!)
Cheers