Can you see the control board? There should be some LEDs illuminating on it near one edge of the board, if power is on.

The manual for the machine is here, starting at the commissioning section:
https://reprapltd.com/documentation/fisher-build-instructions/commissioning/

And the Duet 2 Maestro control board here:
https://reprapltd.com/documentation/fisher-build-instructions/commissioning/

Does it have an SD card in the card slot? I believe it needs the correct one in for the board to start up properly, but I've no experience with Duet 2 boards.

Figured it out. Needed to add M575 to config.g. All good now:

M575 P1 S1 B57600

@dc42
I know. I can't get AU anywhere:(

@dc42 Thank you, sir!