The quality of the gearbox was very, very poor. The gearbox was very noisy. Further inspection showed the central gear only engaged with the planetary gears by 0.2mm! That's not a typing error. Adding a shim between the motor and gearbox of 0.2mm was enough to prevent the gears engaging at all. After several messages with the supplier they FINALLY sent a replacement motor with central gear but the engagement was still only 2.0mm. This is enough for a prototype build but not enough to trust the unit on a final design. Very disappointing.
Had to be resent, but just tested it and it works fine on 24V.