Well I haven't really done anything since but here's the plate I made up, ignore the screws as it isn't quite finished & I've run out of countersink m3 screws. You'll noticed I haven't cut a hole for the access plate, i'm not sure whether to maintain max rigidity & accept the hassle in removing the gearbox if I need to adjust the diff or cut the hole & risk making the plate weak...
One of the two remaining good hinge pin blocks is cracked too
I wonder if these could be 3D printed... Otherwise, not too bad. I'll build the diff, finish off the rear end & make a start on the front.