I've just re-read earlier posts I made re this controller, and think I have the answer.
The Y axis, designed to have a two motor option, needs N/O limit switches.
At least that's my interpretation, and certainly that's the condition in which the motor moves.
So it looks like a swap round for that axis limit switches, though I would be happier with the fail safe that N/C give.
Any ideas how I can get fail safe with needing a low (?) on the input pin ?
Perhaps I'm just being over cautious ?