My Potterton Kingfisher2 CF80 will not restart (12 yeras old)?

Replacing my water cylinder today we switched off the boiler drained down and reset all the plumbing all fully operational.
However when we came to relight the boiler the pilot light is working but the main burners are not firing up.

All the control cables are as this morning and no changes have been necessary.

Un like newer models there is not a reset button on the temperature control unit.

Any assistance would be appreciated as we have no heat as yet.

Thanks

Ed