An end of day update:
Rear brakes have been reassembled, handbrake adjusted up and it's fair to say I now have a good handbrake, with far fewer turns on the nut at the handbrake lever. As you would expect, a pair of return springs will be needed.
The rear subframe bushes have been replaced with a pair of Powerflex poly bushes which I just happened to have on the shelf.
This was the approach I took:
Remove rear bolts
Slacken middle and front subframe bolts
Remove steering rack bolts
Remove top bolt from the rear gearbox mount.
This just gave enough space to get a pry bar in and some wooden wedges to hold the void open. This was taken just before removal of the first bush, a little larger gap was required, only a couple of mm or so.
The existing bushes were totally shot, so the centre section was forced out at the top, while a reciprocating saw (or alternatively a hacksaw blade) was used to make two cuts in the steel remains of the outer part of the old bush. This allowed the old bush to be levered out and withdrawn from the bottom.
Time to put the new ones in. let's just say that there is a technique to this. The first one took a good couple of hours, the second one about 5 minutes.
The key is to be very liberal with the washing up liquid. I used three fingertips full to coat the top and inner part of the void. Then put the bush in place, slightly off centre. Then raise the subframe up with a jack. The bush will start to slide down at an unusual angle, and then all of a sudden it will almost seem to suck itself into position over the last half of the movement.
I have noticed the the centre aluminium heat insulation is loose so some large washers will be deployed to secure that back in place