Timing chain adjusted to 12mm-ish movement, thanks again orienteer and
Charlotte's Tandems. A very simple job. Cranks also aligned.
Squirt of Dinitrol ML down the stokers seat tube.
Brake pads de-glazed on some course emery paper and several bits of what looked like aluminium swarf removed. Brake pivots cleaned up & lubricated and brakes adjusted. Not terribly effective as the only adjustment on the spring return is the choice of 3 holes to locate the fixed end of the spring. Also the brakes are the type where the cable connects to one lever and a fixed short piece connects from the yoke to the other lever. These always pull unevenly. Still, they feel better now.
There is huge lateral play in the hubs but that's a problem for another day.
With that we mounted up and had a wobble, lots of wobbling. Mrs Tween has only cycled a few times in her life so this was always going to be eventful. But after a dozen times up & down the garden & drive the terrified screaming behind me changed to our first 'wheeeee'