With the utmost thanks to Dave, for explaining this in steps even I could understand, and everyone else who also posted and helped, I have now fixed the powerfolds!
Taking advantage of a break in the weather, an early start and a somewhat helpful 17 year old, I took the door off this morning and found the pin was missing in the car side loom for the orange / green wire.
I found a connector the same size in the various looms I now have spare and replaced it, and a quick test showed full functionality restored
One niggle ticked off the snag list
