I use a 4-1/2" angle grinder with a cutoff blade. Just put an angled cut in the ring (doesn't have to be too deep, or even across the full length) taking care not to hit the bottom lip or go too deep. Then whack it with a small chisel right in the notch. I've found it to be much faster/easier than drilling and chiselling. Always splits easily along the notch line.
You don't need that spring if you're working on a S2A. I think that was an earlier type.
I believe the bushing (#27) was a brass piece that was on earlier Rover hubs, prior to the installation of a bearing (#6) in the swivel balls. You shouldn't need it.
61 II 109" Pickup (Restomod, 350 small block, TR4050)
66 IIA 88" Station Wagon (sold)
66 IIA 109" Pickup (Restomod, 5MGE, R380)
67 IIA 109" NADA Wagon (sold)
88, 2.5TD 110 RHD non-hicap pickup
-I used to know everything there was to know about Land Rovers; then I joined the RN Bulletin Board.