How the hell do you remove these, I'm trying to remove my front bumper and in order to do so I know the arch liners need to be removed, I've seen there's 2 torx screws to undo, easy enough, but there's about 5 or 6 of these round plastic grommets to remove too, can't see how they come off, there's no way of unscrewing them as they don't have a screw head or anything on themand I've tried turning them anticlockwise by hand but they just turn but dont actually loosen,