Not so fast.
If that the best the dealership can do for pinpointing an oil leak, I would get a second opinion. The difference in cost between addressing these items is large. If it is all three, you're looking a lot of $$, assuming you're not interested in DIY. If it is just the head cover gasket, its a simple fix.
Question:
I replaced the valve cover gasket, changed the oil and filter and the oil leak is now much worse. I've checked and a far as I can see, there is no leak coming from the valve cover seal but it's below that.
Did you do the gasket replacement? Was it done properly? Is there a chance you're missing a leak at the cover gasket? Did the dealership mention the head gasket? Are you losing coolant? Is the oil ending up on the TOP of the manifold (exhaust pipe)?
The only other way, in my humble opinion, that oil will end up where it is in your third pic, is by dripping from the head cover or head gasket areas. If I'm oriented correctly, oil may be dripping onto the top of one of the manifolds. I don't believe its possible to end up there from either the rear main seal or oil pan gasket. It would have to a hell of a leak from the rear seal through bell housing to get tossed up AND forward.
Do me a favour, find some jackstands and wash the crap out of the passenger side of the engine, the oil pan, the engine to tranny area and whatever else is soiled. Run your engine and see where the oil is coming from. From your description, there should be significant leakage to cause that much smoking This is free, and might just give an idea.
Almost forgot:
There are a few pipes, coming off the engine that appear to have leaks too at the part they join other pipes.
Not familiar with any other sources. Below Ive posted two pics of the exhaust side of my clean M50. You'll see that there aren't many options for leakage onto a manifold. PIcture it tilted the other way as it would sit in your car.
EDIT: Just realized we're looking at the the exhaust from the top of the car and the oil is hitting just beyond the rear manifold. This may be a very leaky rear seal spraying oil out onto the exhaust at higher engine speeds. The second pic below shows how the flywheel lines up with the oil mark in your third pic
Hope this is of some use. Keep us posted,
Dave M