gearbox/clutch oil ?

Frlm the INternet search you could have done:

Highly inaccessible and difficult to fill without a dedicated pump or long thin hose. From Offside, look up at the diff above the exhaust and almost directly above the engine stay bar.

Oil (hydraulic fluid) for the clutch master cylinder goes in the usual place - in th emaster cylinder.

Normal car clutches per se don't have oil.

XXX
April 2016