Here's the extra steel bracing the dropouts which runs around to the two M6 bolts above plus a lugged flatted washer welded to a bit of steel around one of the M6 bolts. It means the wheel can't be taken off without undoing one of these M6 bolts each side but given I'm running a Schwalbe Marathon the chances of needing to do this at the roadside are small. There's 5mm of steel this side and 3mm on the other. There's less there because the dropout wants some room too.
Almost done now bar the cable and wire management to tack on plus the cabling and wiring themselves. The V brake bosses made excellent places to brace the rear carrier rack. There's three 116 link chains there and I'm still short by 8 or 10 links. I do have a 10 speed with a very wide range of gears and a 52T on the front so I'm figuring that is why 3 chains have come up short. I've ordered another one which is a bit of a shock to the wallet as the existing three came from Ali Express but the extra is coming from Amazon as I don't want to wait a month. I actually ordered silver from Ali Express and the numpty sent me gold. Given the shiny gold coloured ones are more expensive by some margin I chose not to complain.
One thing I'd like to have done differently is the calipers are on with the actuating arms at the front. ie the cable comes in from the rear. It looks like it'd have been better to have done that the other way round and loop the cables in from the front. I can't simply swap them without remaking the mounts so will try cabling it up as is first and see if it's acceptable. It'll be nice not to have to rip it apart once built with it being stainless. It's crippled many a drill bit but I think it was worth it.