Brummy

I was about to ask the same.

Any 25/45 or MGF (with ABS) should work with the ABS5.3 protocol.

Maybe find someone else locally who has another car and try it pscan on theirs?

Have you checked that the ABS module is receiving power?
 

Its a Rover 200 BRM that has the same modulator/ecu as the MGF and uses 5.3 protocol. Haven't physically checked the fused 12v supply, but on the basis that the ABS warning light is on permanently, I had assumed that there is power. Not aware of anyone else in the locality with a similar setup so I could try pscan on the car.