thanks for the replys, i got roped into looking at a boiler for a friend of a friend after work with only a screw driver and his by chance his multi meter- im still not 100% but i think its the pcb, main thermistor was in range-spillage stat ok , over heat stat had continuity- its the only thing left really, didnt check gas valve but not even getting to point of ignition-
as soon as boiler is reset even with no demand pump runs and lock out light flashes, almost as if the boiler is in frost protection