Tried the digitising wizard and when the program runs it moves the probe and stops when it hits the target, but instead of reversing, it just stops and after a while it displays "Probe ignore, activated at call for probe" and stops program execution. What are we doing wrong?

OK. Figured out one bit. The scanning program scans "stich" fashion and the docs are slightly wrong, ie:

If the probe trips, the probe is retracted slightly from the trip point at the end of
command execution.

Well, it does not Now the probing program runs, but it only advances a few thou and then trips, without the probe tripping, so apparently does it trip on noise. Must put a scope on the input and look.

The probe is quite like this one:
http://www.vinland.com/Touch-Probe.html

And the breakout board is a:
http://pminmo.com/4axisopto/4axisDIYopto.htm

Probe connected to pin 11