Well everything you chaps have suggested is correct.
I did have an E board and I've been sold a P board. So the technical question is probably solved.
Now I just have to see if the shop will give me a free swap. If not I may try cutting that link.
Thanks for all your help. Fingers crossed...
Disconnecting pl9 made no difference.
I can't see a permanent pilot light through the inspection window. Sorry I can't be more exact about the type of combi80. I'm sure it didn't make a constant noise before though.
The board I was supplied with has a few less components on it than the old...
I think one of the pins for a plug on the board wasn't making good contact. This caused the whole boiler to lose power intermitently and finally the arcing melted the board.
I've just replaced the modulator board on a combi 80 and now there is a constant running noise as soon as I switch it on at the mains. Even putting it into standby wont stop the noise. I don't think it's the pump, could it be a fan running? Any ideas how I could stop this/ adjust the timing...