Update and workaround.
I have used Orly Andico's code (
https://www.andico.org/2014/04/ardui...ontroller.html ) to make an Arduino with Adafruit motor control board look like a Moonlite focus controller. It mimics the command set, so the Moonlite ASCOM driver works. Andy's code uses a Version 1 Adafruit MotorShield, I have adapted the code to the newer Version 2 shield design.
I would still be interested in looking at the Starlite DH-1 driver, if anyone has a copy.
Cheers, Ed