Chris
Deano's suggestion is a good one. My car will be up on my four poster this week with bottom off (starter motor change). Any chance you could identify where oil is dripping down and I might be able to come up with couple of places from which oil leaking? Like Deano, I think RMS unlikely. Equally doubt it's seal on main bearing entry into gearbox.
Have you checked that fluid on ground is indeed engine oil and not a different fluid?
Cheers