The cab is all set up to go and when I close the circuit breaker a loud hum starts, but the unit will not move. It also shows power as being applied too
Is the independent brake off. As you sure you held down the battery switch for 5 seconds on the right rear wall of the cab before closing the CB and raising the panto.
Is the square around the throttle setting in the HUD red? That means an interlock is in place (brakes or doors). Check the doors, and then try moving the throttle to Min and back to Off and see if it resets. Also, do you have AFB on but set to 0 km/h?
It looks like the parking brake was on, I have now fixed this. I was thrown because I'm not used to having the parking brake on!