“[86]. Thus, when the vehicle starts to move, the control over arm movement switches from moment limitation to working range limitation. I find it impossible to interpret this in any other way than that the moment limitation device is disabled when the vehicle starts to move. In his evidence in chief Professor Plummer said that it did not constitute disablement. But in cross-examination he accepted that when the Aichi I machine was in motion, the moment limitation device was switched off. I think that is plainly correct and that this amounts to disablement of the moment limitation device.”