A tip from a Lexus mechanic when removing the lens cover - it pulls straight forward toward the bumper - not out to the side as you might think. Also, I only needed to remove one of the clips on the black plastic cover and then underneath is the sheetmetal screw which is removed. My lens cover proved stubborn to slide forward, don't put pressure on the lens as you may crack it, push on the metal piece which the screw screws into.
Hope that helps.
OPLEXFAN