I'm not sure how long it took N-V to recognise a problem with the front brake. I'd mentioned it a couple of times when I was riding the prototypes on test. I found that, once the brake linings were touching the drum, you could keep adding pressure to the brake lever and seeing travel of it without any change on braking effect. My take was that the lever wasn't strong eough and was distorting as the applied force got greater. There was talk of a redesign, but I don't know when (or if?) it got resolved. Once production of the Commando got going at Plumstead Road, the Wolverhampton R&D didn't see Commandos again very often.
IIRC, the brakes were sourced from Italy, but I don't know who the manufacturer was or whether the handle-bar lever was part of the out-sourced system.