I’ve now spent another few hours in the garage and managed to get all the CV-joints apart and to unbolt the flywheel.
Thanks to a recently acquired 600 mm breaker bar the flywheel bolts came off easy, except for the two where a PO had partially stripped the heads. Out came the hammer and with a deep breath I tapped the XZN bit into the bolt. Luckily, they both came off once the bit was in place. A great relief as having to resort to grinding them down would have delayed me considerably.
Disassembly of the driveshafts were smooth, if messy, sailing but as I suspected they were all past their best with pitting and/or severe wear on all parts.
Now I need to find someone who can resurface the flywheel, or if its worn out, order a new one.