Boiler will not fire

I fitted a new GT155 PCB in the boilermate 2000 to resolve the central heating staying on, this has worked fine for a coulple of weeks, and this morning the boiler failed to kick in and produce hot water or heating.
The store light on the LCD lights up, I have no error messages from either of the two sensors, and the boiler pump LED lights up the the pump runs but the boiler won't fire.
If anybody can advise whether the fault is likely to be with the Boilermate PCB or the boiler PCB, that would be great.
The boiler is a glowworm 60FF if that helps at all.