Normally its the motor at fault where you will need a replacement motor, I had mine fail on my other Wedgewood Blue 75
Ã‚Â£450 for a new motor from X-Part that was on back order for 6 months at the time.
Mine would work up and down but soon stop again, all the electrics were checked along with the switch panel but the motor was found to be at fault (was covered by the warranty so the motor was ordered).
If I remember you could try reading the voltage at the multi-plug at the motor to see if you are getting a 12v battery reading when the switch is pressed. Get hold of a switch and swap it over to eliminate that its not the switch board at fault (but did you say that the motor is working) or is it the relay kicking in you can hear?