Why grind the link pin head off, turn adjuster and slip chain off sprocket, remove chain when s/a is off.
To remove hub,
Unbolt and remove caliper, torque arm bolt, caliper bracket circlip, caliper bracket, 46mm hub nut, sprocket with carrier.
Pull axle out from the right hand side and loosen pinch boltan remove hub from the left.

3 problems.
1. hub nut will be tight but you have undone that one
2 hub may be wedged with grit, so open s/a slot with boulster chisel or similar and rotate/ rattle the hub to dislodge grit.
3. large circlip tight even with correct pliers, so open as far as possible and slip narrow blade screwdriver under
the circlip close to one of the eyes that has lifted clear and lever off to start it, then work around, still maintaining pressure on the pliers.
Drape a thick rag over to prevent loss/injury.

top man, you don't work for Haynes then :-)
yes i did consdier that, seemed prudent whilest i was stripped this far to order the SA tool and remove that too and check/grease the bearings in there. I suspect they'll be fine as the lower linkage is spot on. Unless the later has been replaced that is