Looks like this? or double cardan joint?

It's a double joint and the outside of the drum has small Finns on it on the joint are 4 x circlips but when you undo the 4 x bolts the outer boot comes off and slides back over the shaft, then the drum slides back off but the chassis fouls it from sliding back and I can't see how the drive shaft or the double joint comes off

OK. Undo the the drive shaft from the wheel hub and remove. Take the outer drive shaft off the car. Remove the MC if in the way. Now you can slide the drum down the inner shaft and remove it from the car. Do not fiddle with the double, leave it.

Blimey such a lot of work to just change the shoes a friggin nightmare took me 4 hours today and have not even got the shoes off one side yet, thanks for your help I will muster up the enthusiasm to continue one day. Who ever designed this wants hanging

That is why Citroen changed the design on the drive shaft later on, to the 6 bolt removeable system.

PS. Just spotted that your 2cv is a 435. That infomation would have been helpful earlier.

Yes I can see why they changed the design!, sorry yes the dyane is a 435 1972. The Haynes manual mentioned nothing about removing the shaft from the hub, but it was a bit vague trying to cover all the revisions of drums/driveshaft changes. So I got to undo that 32mm nut and remove the hub to? And steering arm? I suppose it will become clearer when it's in front of me, thanks for your help.

The split pin and outer nut, yes. Nothing else. Undo that, push the shaft inwards until the outer splines disengage, then pull back out to split the sliding joint.

I'm really surprised that a '72 Dyane's on the older driveshafts. I thought they died out in the late '60s?

Does seem odd, but at least one 1971 Dyane I've worked on had those 4 stud/double cardan driveshafts.
Lucky for me that the Dyane 4 I've got, which was registered in 07/1971, has the later style of driveshaft...

Thanks all ill give it a go at some point, I may have to cobble a centreing tool another way as the inner shaft and cardan joint thing will still be connected. I think I may buy a complete wheel cylinder rather than a repair kit from ecas as I don't want to have to take all this apart again if it leaks again.

Pm sent Viking