Glowworm EP40F

[Daetont]

Hi I have an old boiler,Two lights stay on,on the pcb board.I think this is telling me the fault,any advice will be greatly appreciated.
The lights are 1 and 2 .One switch live/fuse
2.Thermostat overheat.The fan turns but the boiler doesn't fire
Also does anyone know what sort of voltage I would expect across the spark electrode ignition lead?I can see this def needs replacing.
Many thanks...