Halstead Eden CBX 32 boiler fault?

Hi

I got a Halstead Eden CBX 32 boiler about 2 years old, the heating is not switching on from the clock. There are no error codes/alarms displaying, and if I switch the boiler into service mode the heating comes on. The DHW works fine so it justs looks like its the heating side of the system. Have checked the output of the clock/timer and there is an output voltage when the clock is switched on and the pressure is OK.

So could it be a micro switch or PCB fault ?