Well, I have been making a little more progress with the bike (still very slowly!) - the headset and BB bearings are back in place, the paint job on the frame is finished, and the rod brake bits and bobs are halfway cleaned up/painted. Pics to come soon!
I took the old hub and rim into a couple of bike shops to ask if they had a removal tool for the freewheel, and what sort of spokes to buy... and both said the wheel's not worth rebuilding (due mainly to the still-wonky rim). One of the guys saying this owns several rod brake bikes, so I guess knows what he's talking about. So I need to source a new back wheel at least, and possibly a front one too - Flying Pigeon do some suitable ones, but don't have a front wheel in stock at the moment, so I'm still searching around for the cheapest solution!
I took the finished bike out for a ride with my wife, parents, sister, and brother-in-law today, down to the coast along the Exe estuary - unfortunately it pee'd it down on the way back home, but was still a lovely ride, and I'm very proud of my wife for managing a 42 mile round trip
Back home, I noticed the wheel bearings have loosened up a little so the cones need tightening up a little - a nice little job for a rainy day!