I must have been incredibly lucky!
Unlike you super smart electronic wiz kids (what is a 47nF across the supply lines?!), I am an electrical bimbo, but I followed Simon Gregory's lead and mounted a Hall effect sender to take a signal off the 3 prop shaft nuts at the back of the gearbox, and it worked straight out of the box.
So glad it did as I would not have had a clue how to deal with your issues: I marvel at your knowledge.
