Any
oil leak will ultimately find its way down to drip off the bell-housing, giving the impression it is coming from the RMS.
I had/have exactly the same issue and went to all the trouble to pull out the gearbox, clutch and flywheel, only to find the rear of the engine completely dry and free of
oil i.e. no leak from the rear crank seal.
I think mine is weeping from the front of the engine somewhere because the lower flange that the sump bolts to on the timing cover is pretty gunky.
Paul