Thanks Raymo, I think it is best that I don't play around with the actual control unit which has so many wires i wouldn't know where to start, probably best to get a sparky in for a look.
I just wondered if one could test the unit when taken out of the system and using a Battery maybe to see it it clicks when touched on the terminals.
Your right two failing is probably not on and I do expect it will be in the actually control box somewhere, but not for me to find.
The water valve is fine and passes water manually.
Leon