And here's a shot of the dismantled parts sitting on my work bench. I've numbered them so I can refer to the parts as this thread progresses.
1 Keeper. This is keyed to the axle and holds all the parts in alignment.
2 Shift Cage. This fits inside of the keeper and is keyed onto the actuator arm that rotates about the axle and depresses/releases the sun pinion pawls. You can see that the are two internal tabs that are pressed into the base along with a cutout for keying to the actuator arm. There is also a torsion "override" spring with a hook at each end fitted inside the cage. The inner hook of the spring abuts one of the tabs, the outer hook keys into part #4. The purpose of this spring is to allow a shift to be started even if the hub is under pressure and cannot execute the shift until pressure is released (e.g. at top dead centre when pedalling pressure is reduced). In theory the spring could be rotated around so the hook sits on the other tab, or the protrusion of the actuator arm, but you will see later on that it needs to be as shown in order to correctly orientate the parts - I figured this out via trial and observation.
3 Spacing Bush. This has a small notch that should face into the centre and be set over the hook of the override spring. The outer hook can be manipulated with a screwdriver so this bush can be pressed down firmly.
4 Inner Spring Cage. This has a protrusion with a notch to hook the spring from part #2. On the other side it has a protrusion with a notch to grab the lower hook of the shift spring (#5), along with two keyed notches to fit with the drive key (#8). It can only fit one way, the notches need to be facing out.
5. Shift Spring. This torsion spring supplies tension to the shifting cable. There are two outward facing hooks, one slightly longer than the other.
6. Outer Spring Cage. This is keyed to grooves in the axle to prevent it from rotating, along with a hook that needs to face the shift spring so that the spring can be tensioned correctly.
7. Clutch. This shifts the gearset between the upper and lower ranges.
8. Drive Key. This rotates the Shift Cage and the outside end is keyed to the driver for the shifting pulley.
9. Pawl Tripper. This triggers the clutch.
Parts on workbench