Thanks for all the very helpful replies.
Turns out the new motor remote control goes through the loom direct to the motor, so this old setup is redundant. I fond a wiring diagram once I know what I was looking for.
Thanks again folks - we will be back in the water in time for Christmas (it's...
Now I can upload the image by making it smaller:
So I think tilt solenoid is correct - clever Jakedaawg working that out without a photo - any idea why the faded green wire is cut?