Thanks to you all, but especially RobbiZ4.
I have just done L/H side. Unfortunately went straight to youtube video before reading this and took nuts off without marking.
Put them back noting the wear marks on the car and scribed around nuts heavily with small screwdriver.
Gave up drilling the soft M3 bolts and unscrewed them easily with old side cutters gripping the heads.
My solder skills are good so preferred that to messing up the connectors. Used heatshrink, sleeving and hermetic tape.
Cut new M3 bolts and tapped them. Found some threadlock in shed.
Ensured cable goes on outside of assembly as per the many photos taken.
Put trim back and tested roof and boot mechanisms.
All good, if not I would only have had to inspect, adjust one side.
Now after a cuppa, off to do R/H side with a little more experience.