On both sides, underneath the sill and just in front of the seam underneath the car are drain holes with black circular plastic plugs in. About 6 of them roughly evenly spaced. But the front one on both sides doesn't have a plug. Is this the usual case or isn't it just mine missing them? I assume its too allow for drainage but why then are the others plugged? Wondering if I should plug these up or do I run a risk of allowing water to build up in the bottom of the sill. no photo I'm afraid but it s bit dark out there and didnt have phone with me.