Thanks for that - an interesting discussion although ultimately inconclusive. I don't think the problem can be my battery - otherwise, why would it fire up so readily when we made a direct connect from the battery to the starter motor.
If it is a fault between the starter button and the starter motor, why are we getting current at the starter motor when I press the button.
Why won't the damn thing go?!!!!!
(That was a rhetorical question - I don't expect anyone on this forum to know the answer.)