Thanks Bois!, plenty to think about .

Pay attention not to damage the glass brake fluid reservoir.

Glass Reservoir by Robndaisy, on Flickr

I haven't looked at it yet to see if it's serviceable, but it looks flamed to me! Maybe this would do? https://www.ecas2cvparts.co.uk/reservoi ... -1298.html. I'd probably fit the clutch and brake lever box afterwards .
Might make a frame on castors to hoist the engine/gearbox in and sort out the floor, £35.00 to hire an engine crane for a day,+VAT and I just fancy making one.

Don't see a problem. Mine did look almost the same. If yo get the lid off there is a big hollow bolt inside. A sparkplug wrench will fit on that. It might be rather stuck. And pay very much attention not to shoot of that bolt, you kill the glass then.
Bye the way looking to at the picture i see a nut under the glass/metal cup that is not original. But you can screw it off. Than put the hexagone in a vice and give it a try with the hollow bolt. If it's still there....
No problem in fixing brake/clutch assembly later.

P1010654 by Robndaisy, on Flickr

P1010655_LI by Robndaisy, on Flickr

I was just looking inside it in front of the laptop and saw this pin hole so that is that. It has been too long left dry,what a shame, the thread is M16x1.5 though, so a plastic reservoir will fit.

Couldn't you solder the hole?

If there was no alternative I would mess around with it, but because it's the brakes, it has to be right, I can't really compromise. In the future I will try and find another one. It will join the old cooling fan, hanging on the wall .

P1010657 by Robndaisy, on Flickr

Back together again, hopefully for a long time! Used a kingpin drift to more or less align the friction disc.Gently tightened the 6mm. bolts to allow the gearbox shaft to nudge the friction disc into line as it went on.

P1010658 by Robndaisy, on Flickr

Once it was on, tightened three bolts , worked the lever a few times and took the box off and torqued up all the bolts to 8 lb.ft. Put the box back on, Happy Days!
Next, make something like this http://guillon2cv.free.fr/documents/dic ... che17.html. Have decided to hire an engine crane instead of making one, it can lift the engine/box down onto a trolley(that I will make) and then trundle it down the garden path to the tent.

P1010659 by Robndaisy, on Flickr

P1010661 by Robndaisy, on Flickr

It might just work .

Ready for take off...