IMHO, best left to someone who knows what they are about. I am not saying that you are not.
IF it is the PCB, then eventaking one from another boiler, it might blow the other board.
Maybe the board has gone due to another component failure.
To the OP
The glendevon is one of the pricier kitchens, that Howdens do. Also you have a few decor panels and curved units...they jack the price up on any kitchen from any supplier.
Personally find howdens kitchens to be one of the best out there.
Fitted around 60 of them to date, so have...