As has been alluded to, the workaround I used on my ARP4 in the 10 years I owned it, and passed on to every MOT tester, was that the car should be set with the footbrake hard on first, then the handbrake pulled up, this then held the calipers in the position set by the footbrake. No-one says that the handbrake has to be used to slow the car, only that it should hold it in a parked position. It certainly worked for all my MoTs. BTW, the handbrake on my '24MY Plus Four grips like iron.
