OK, time for an update....
I've obtained another transmission tunnel section so I can get on with the gearbox install. I have also grabbed some "A" pillar sections to repair some small sections against the pillar drip rails either side. I have also borrowed an original pedal box adapted to running dual masters and a bias bar which I intend to copy. All thanks to Matt

As the panel work took a back seat for a few weeks I have turned to the rear disc set-up. I've decided to go with R31 rear callipers and Audi 90 rear discs. I chanced across this set-up whilst researching on the net but for the life of me I cannot find the page again [:(!]
All it requires is a simple straight adapter bracket attaching the calliper to the housing flange. The axle flange requires the diameter to be reduced by about 10mm to allow the rotor hat to slip over. The Audi disc is already suited to the 4x108 PCD of the escort axle.
Below are some images of the callipers and the original R31 bracket.


Playing around with the original bracket it appears that bolting this to the housing (in the same way it's used on the R31 diff) the offset required to suit either the Audi or R31 rotor (both approx 60mm) looks close although fitting and checking with the actual rotor is required. The only difference being that the R31 rotor has the wrong PCD (although can be ordered blank) and is a larger diameter (260mm to 245mm). My preference is the Audi rotor as in the future it can be replaced with zero mods required and I think it's a more balanced set-up with the 2.8i front rotors (247mm).
Below is the calliper bolted to the Escort housing (sorry but the pics are from my phone [:I]) The PCD of the R31 housing is bigger than the escort and will need to be re-driled if the offset etc is suitable. If the R31 disc is used then I see this as a possible straight forward converion. The Audi discs require a custom mount.


The rotors are $60ea so I'll order them and start matching it all up