Hi, I'm reading this also. I have the same problem in my Seat Toledo (Skoda Rapid) 1.6 CR TDI CXMA (clamp was removed, clearly can see it's from EGR)
Not really smells like oil, but better yet, the undertray looks like this after cleaning the spot where it dripped (i used brake cleaner to get it off, i sprayed the whole undertray so it's not like that brake cleaner did the damage):
I don't think that oil would eat plastic like this, but I believe that G12evo coolant would eat plastic like this. I think this is coolant + exhaust, but my coolant level hasn't dropped (altough this "seems" very little loss of coolant to be noticable, that spot in the undertray is 12.000 km)