Now with the two of the Omniwheels installed I attempted to get the Rover to spin on the spot.
Still no luck so I lifted the Lead Acid battery and saw that there was some movement.
I have a power pack that was part of a Solar Cell pack.
This pack has the ability not only provide USB power but also a 12 V output via a 5 mm barrel connector.
I created a cable and connected it into the stack.
Programmed the Arduino to spin the wheels, one side in one direction, the others in the other.
This appears to have almost worked.
I say almost because I was hoping for it to rotate on a spot central the Rover.
It appears to be rotating at a mid point between the two front wheels with the rear wheels slipping.
I made tried programming the Arduino to just rotate the front wheels, however it juddered a lot.
A further experiment was to increase the speed of pulses into the motors. This gave a smoother rotation, still between the front to wheels.
Now note that this may be because the the front wheels have a lot more traction with the ground, the Omniwheels are not so 'grippy' and think this is why the result is what it is.
I will try putting the old wheels back on and see what happens.
Here is the video of the initial experiement which has the ok result.