Well, you know how it is with old cars - you fall in love, you make the purchase, the vehicle arrives and, well, there is a lot of work to do - much more than you thought.
Somehow I end up with the job of fixing brakes, perhaps I am overly interested about stopping when I need to, am I fussy to expect this? Have a look at the brake fluid drained off this van:

It is meant to be pretty clear, not black - that is shocking! No wonder the brakes are seized. The clutch fluid was the same.
The passenger side rear brake drum and linings were saturated in grease - suspected leaking hub. This was easy to extract and replace. However, it meant my brake linings and the cast iron hub were greasy, what to do? Burn them. I was advised to place the linings in the drum along with some methylated spirits and to burn them repeatedly. I did this a few times until there was no more black smoke (indicating no more oil I expect).

The rear cylinders were taken to the brake shop
(
http://www.autobrakeservice.com.au/)
to be
resleeved in stainless steel and new rubber kits were fitted.
PBR part numbers (sadly their internal part numbering system, no
OEM details):
P6892 - rubber seal kit
K263S - rubber seal kit (can use 210K0142)
All up - dismantle,
resleeve, rebuild - both rear cylinders (always do these things in pairs) $300
AUD - 150
GBP approx.
They were able to locate a kit with the special "boot" that fits over the handbrake lever, hopefully keeping the dirt out for a little longer (see below).

Also note in the image above, fitting the bleed valve / inlet banjo union first, then attaching this to the brake cylinder using the banjo bolt. I think this leads to less stripped threads... but I am not an expert.
The small washers between the banjo joint and the banjo bolt and brake cylinder are made of soft copper, that compresses to seal the joint. When reassembling, you should use new washers, or you can "
re-anneal" the old ones. Using a small blow torch to heat washers dull red:

After assembly:

When fitting the drum / hub over this
arrangement, I suggest setting the
Micram adjuster (just below the piston part of the cylinder) to its lowest setting (turn it anti-clockwise).
Well, after all that, I am going to have to do the rest of the system. So to the other end of the car to extract the master cylinder and clutch hydraulics...