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...
Ok Then
As you have a 30kw at the moment, and realise its capabilities, then go for A vaillant 831. Good boilers. Personally the exclusive is not worth the extra cash.
More important than the brand of boiler, is the quality of install.
I have seen a few dirt cheap aristons installed that have been really well installed, and many wb or vaillants that have been installed terribly.
What are your incoming cold main flow rates?
IMHO, a 32 kw combi will not be...
160mm is more than enough gap, to erect a sort of false wall in which the pipes can be run.
2x2x should be adequate, and allow enough room for plasterboard/aquapanel and tiles.