Ok I'll stick to the one motor, it was only that it fit quite nicely having 2 motors but 1 will work. I also figured that whilst there was more to go wrong it also meant if there was a failure of one motor, belt or ESC it would still keep working for the rest of the fight or even for the rest of the competition.

The plan with the wheels is to have them come back over the motor/gearboxes allowing me to have reasonably wide wheels but still keep the robot narrow