Thanks ollski,
The electrode lead was connected correctly at both ends.
Have disconnected lead at electrode end and held to earth as system was running up,(Gas off ofcse).
Had the weekest of sparks across to earth untill ignition sequence(green light flashing rapidly). At this stage week spark stopped and resumed after ignition.
Tried the same sequence holding end of lead to back end of electrode pin, no spark across lead during run up or ignition??
Also held screwdvr across back end of spark generator connection (no lead connected). No spark across screwdvr wether to earth or not, either at run up or ignition.
Any ideas please