[ATannahill]

The answer to the question specifically asked is to multiply by a constant of -1. I believe, I am not heavily versed in this area.

If we dig deeper we might actually find the problem. Could it be fixed by reversing which wires are connected to the motor controller? i.e. swaping m+ and m-. This is not the proper solution if forwards and backwards are working correctly.

Is this default code you are running or have you done any work on it?