Managed to weld in some tabs to bolt a piece of diamond plate ally.
there is only 20mm of space, so anything I do in there will be tight.
I have a combined regulator/rectifier that I got off ebay years ago, so to make it fit and look (and be) a bit cooler, I have sunk it into the plate so the fins for the reg/rec are in the cooling air.
I am going to install a couple of relays in front of the battery along with a couple of inline fuses. The relays are for the headlamp low/high beam and one for the horn due to the lightweight switches on the handlebars.