I did mine last week, If you take a peek it screws to the outside of the wing in the centre, just take out the screw and carefully push the liner behind the tab that the screw was held into. then if you feel you need it you can bend the tab further into the inside of the arch, but be careful doing this as i broke the paint seal and a piece flaked off. So i now need to just touch up a bit of the paint on the tab as the primer is exposed on a tiny piece.