Liam1961, thats interesting, ref use of footbrake first and then apply handbrake. I must try this out. I assume the Plus Four rear caliper is similar to the Plus Six?. The Plus Six handbrake mechanism is part of the caliper and basically uses a mechanical internal mechanism to push the brake pads against the disk. This is operated by the handbrake cable.
By applying the foot brake first the pads will have already been hydraulically forced against the disk by the main caliper pistons, the handbrake mechanism then basically applies its force against the already holding pads. Maybe it can exert more mechanical force this way and that is why the handbrake will hold a little better?. Some time ago I did try to track down an exploded diagram of the rear calipers for our 2020 Plus Six to try and figure out the mechanism, but apart from external photos in the manufacturers supply catalogue I found little else...
