OK not come across this on the forum so far

Rear wiper not working, all wires (except earth) are live regardless of boot position or switch usage

Relays click when stalk switch activated

Fuses all fine

Have changed motor, and stripped down to check the return sensors are making a good contact

Any clues anybody?

Common problem. I had two wiper motors replaced under warranty. Water for the rear screen washer jet gets into motor/gearbox as the pipe passes through them.

That's what I first thought, but have changed motor - tested it in another car and it is fine