DapperDan , Dave and Paul Thanks for the comments
MrT May be when i retire i may set up a small machine shop with a cnc bed mill to do one off bespoke parts. This is something i have thought about after seeing your side mirror mounts, so will definitely look into how i can possibly lift the mirrors up.
Made a base out of 3mm ally plate for the fuse board to mount onto.
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The cut out is clearance for the wires that attach to the bottom of the fuse board with a couple of spacer's to lift the fuse board up slightly. The hinge is to gain access in the future.
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Plate and fuse board in position on the passenger side behind the dash board area, a length of 8mm studding welded to the 20mm box section is used to lock the plate in position with a wing nut to drop the plate down for maintenance, this can be seen in the second image.
I am thinking that the safest position to run the wires from the front to the rear of the car is on the passenger side down in the sill area, I've bought a length of black plastic conduit that i will put in the sill area before back filling with expanding foam, the tube will allow in the future if needs be any cables to be replaced may be a bit over the top but while at this stage it easier to do now.