After the other night my old fella went to the unit with a list of things to check, I mentioned the spark in the exhaust manifold and:

He removed No1 spark plug( where the head gasket popped originally) and the spark from the HT lead was all over the place (maybe water damage), swapped the plug lead for another we had and it now works.

Not seen it myself or heard it but i have been informed all is well, cheers Glen


Steve