I opted to cut the well around the vertical walls, extend the walls on the well using G10 + carbon fibre along with general reinforcing around the area and then glue back in. This way the interior remains unmodified as I could attach the bolts before reinstalling the whole anchor well. Still have some tidying up and painting to do, but so far it works well and makes for much easier single handed anchoring. If anyone is interested in doing a similar mod, the original fibreglass well is quite thin. There is ample depth below it for a drum winch so I made it deep enough to be able to close the hatch. There are some winches on the market smaller then the one I used that might fit with more room I would imagine.
The wiring also fit behind the lining on the interior down to behind the galley which was nice.
Before anyone comments about the anchor swivel the setup was just to check the fit. I've since added a shackle to allow pivoting without risking pronging it open.
I hope it helps anyone looking to do similar!
