When I was changing the wheels on my car today for the winters I noticed there was a bit of oily gunge starting to seep through the join of the undertray and splitter.  The only thing I can think of is either some air con oil or that the inter cooler pipe is leaking slightly.  This being the case I suppose its also leaking a bit of boost...  
I didn't have time to take the undertray off or investigate further but does anyone know if there is a seal ring or is it just a clamp thats likely to need cleaning and tightening.  Leak observed just forward of the drivers side wheel arch.
edit:
Anyone got a part no for the seal ring?