Been doing some work on sorting out the underseal on my 147 and noticed that I might be missing some rubber grommets?? Just inboard of the rear jacking point there is a plastic cover with a hole in it - through the hole I can see the floorpan and there is a big 2cm diameter hole that looks as though it should have a grommet in it. It is the same on both sides. I'm not getting any leaks (yet!), but can anyone tell me if there should be grommets there or are they some sort of "ventilation" holes??