You don't need to touch the hub nut. if you have the standard drum rear brakes you can undo the 4 bearing hub bolts through the drive flange, the complete shaft will the pull out from the swinging arm and the shaft will be out of your way.

If its had rear disc's fitted then un bolt the drive shaft at the diff which will allow you to swing it out of your way to give you more room.

Anti roll bar, take the two mounting bracket bolts out and allow it to drop.

Flexi Brake pipe. clamp and disconnect, levering the swing arm down to get the spring out will over stretch it and you don't want that.

Having done all that your still need to lever the standard spring out of the swinging arm or if you have a small bottle jack you can place it between the swinging arm and the chassis rail and jack the arm down.