A little esoteric point worth mentioning is that the axle nuts on the Nexus are 3/8" 26 tpi, not a size you may necessarily have knocking around in the bits bin, and the standard 'acorn' nut needs far more axle to grip than a flat nut. I'm using the thick lock nut I removed from the innards as a stopgap, obviously not a long-term solution (not least because it needs a 17mm spanner).

Vintage British motorcycle suppliers seem to have plenty, I've ordered a baggie to be on the safe side.