Redoing the rear lights was not as big a job as I thought. Took longer to take fenders off. Came down to a simple bit of grinding and drilling two holes.
So here a trial fit after doing one fender. (the paint did suffer from unbolting all the bits, so after taking these pics I stripped the paint off and repainted - as you can see, sanding did not work well on diamond plate)
The light is at an angle because the screws are not tightened yet.
Can barely see where the wire runs through the fender.
Back side before cleaning up and filing of the sharp edges.
Will not have to drill a bigger hole in the frame. The wires fit through the existing 2mm holes.
Wire can run along the middle support of the fender and then go behind it
To come out on the side and disappear in the frame.
Now waiting for the new paint on the fenders to dry before reassembling the lot and running the rear light wires to the front.