Yesterday, I took delivery of the hydraulic crimper, cables and terminals, and had no trouble in making up the lengthened leads I needed.
This afternoon, I installed them. Then I hit a problem. Or thought I had. I was getting a long "beep" from the motor. There are high voltage, low voltage and high current warnings and cut-offs, but these make a short or fast-short "beep". The manual is badly translated from Chinese, and under "long beep", it just says "Motor stop operation, wait the throttle back to neutral position".
Then I had a lightbulb moment. I hadn't put the magnetic kill switch in place. This is not mentioned anywhere in the trouble shooting section.
I put it in place. Problem solved. The prop now whizzes round. It's quite noisy for an electric drive (out of the water), but nowhere near as noisy as a petrol outboard, of course. I think I'll be reassured if I can hear it going, and how fast. If it were completely silent, that might be too little information.