Thanks. Neither option seems to work right now. The speedo/odometer works fine using the motor hall sensors, but seems to ignore the white wire. Is it possible that I need to connect the spoke magnet sensor and re invoke the self learning mode?
Also, when I first got this running, I used a couple of resistors to emulated a throttle voltage, and stepping through the assist levels changed the speed proportionally. I then connected the throttle wires to the rear dropout torque sensor, and something changed, so that the assist levels seem to do nowt. Back to the resistor divider and also only the one speed. I'm wondering if I've accidentally screwed up some other setting, and whether there's either a list of default values for the settings, or a way to do a factory reset.