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Will I need to remove the swinging arm in order to remove the shaft - i.e. can pull it out after removing the bevel box?

Yes you can pull it out - actually it comes out better if you ease it with a large flat blade screwdriver.
It is fastened to the gearbox output shaft with a wire snap ring.

but you will probably find it is easier to replace it with the swing arm off. I tried to engage that end on to the gearbox via the swing arm tube, no chance.

Remove bevel box, undo the ties around the gearbox & swing arm, as stated use a large flat blade screwdriver at the gearbox end and lever out.

to replace align the universal joints (let the debate begin) insert shaft into the gearbox output.

When pushed fully home smack end of shaft with a copper mallet and the shaft snaps back into position.

Simples

I am so disappointed with this thread.