Habot H GL5 80W90 hypoid gearbox oil
This oil is sinthetic and lasts about 100000km before replacement and is available through Bearing Man dealerships also improves gearchance
Castrol makes a synthetic oil, not sure of the name, but it costs in the region of R186 per 5 litres (brought it through a friend of mine wholesale price). This was used in the Gearbox, not sure about the Diff (I would say not). The balance of the oil I keep in my garage, so that when the bike needs oil, I can top it up from this container, so that the bike always has synthetic oil.