Hi Kevin,
I have a 1950 Slough 6 that was sold new in South Africa, it then did Australia and New Zealand before returning to Johannesburg and then being sold to me. 18 months ago I did the brakes and could not believe how hard it was to reassemble. The most annoying thing is the small bobbin spring anchors which of course fly across the workshop never to be seen again every time you try to attach the springs. My solution in the end was to assemble without the springs to find a suitable place to drill the 2 sandwich plates and the aluminium spacer, I then used small countersunk screws and nuts to bolt the unit together. The whole assembly can then be built up on the bench and fitted as a cassette. I found this method worked well and will make subsequent strip down and assembly much easier. I hope this helps.
Good luck Philippe Allison