Great advice ROB, I read that somewhere before and did exactly that. Just got in from a whole day under the truck, quite a learning experience!
So, advice to others attempting the same with numpty grade knowledge...
• Make sure you have the tools to access all plugs.
• Have a good bucket or pan for collection of silvery stuff that comes out!
Tackled the rear first, the filler plug is a sod as you need a knuckle and extension to get the angle past the syncro underbody protection bars. I cleaned out the 17mm recess with a small screwdriver so I could ensure a good bite from plug tool. Came out really easy. The complete sod was the main drain plug, I had assumed easy access (you know what they say about assumption!), but the sump protector (late type in my case), completely obscured access for allen key / plug tool etc. I tried the using a 10mm threaded nut on bolt, but it kept undoing, rather than the plug. So eventually managed to put a jack under the protection plate and get the plug tool in. Pic here with double-nut arrangement:

The rear plug looked like a christmas decoration, which I guess means it was doing its job! Refilling was a little slow. I used a standard length of hose (clean spiders out first!), with a hoselock connection to take an
ex-kitchen funnel [she never used it anyway!]. Handy having a doka as there is a convenient bed for the tools! Managed to get 4 litres in, as suggested on the syncronauts website.

The front was a piece of psss. Easy access, and took 1.5 litres of oil.
Thanks for the guidance. All made easier with my new mini-pit, with carpet!:

*no idea why the pics are sidewards, all good on my pc?*-
Gary.
1990 Syncro DoKa (RHD), 1.6TD.
"ein Leben lebe es"