As others have said, only sources for oil from the bellhousing hole are;
Dodgy clutch slave cylinder
Gearbox input shaft seal (unlikely)
Engine output shaft seal
And I'll add, possibly, oil dripping somewhere behind the engine and getting into the intermediate bellhousing through the top slot where the steering rack sits. Also unlikely.
Only the last one is at all likely to be a quick and easy fix, others need the engine out.
Good luck with sorting it out.
