SundanceUK

Passenger side window is controlled directly from the switch, the drivers side has relay control from the BCU because of its semi automatic operation. It will either be the switch, broken wires in the door where it hinges or the window regulator unit (motor) at fault. Switches are easiest to check and would be prime suspect.
Also the window regulators have a plastic bevelled drive gear that can wear, causing intermittent operation, but usually it goes down but not up when this occurs.

Sundance