When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
You need to open the door to access 2 of the bolts for the wing. You also need to remove the inner wheel arch shroud and separate the wing from the bumper (clips/screws etc).
The bolt at the bottom of the wing, by the wheel arch will no doubt be covered in underseal/paint. You need to remove this before attempting to unscrew the bolt. However, be prepared for the bolt to have rusted and shear when applying any force.There is a captive nut on the back, so if the bolt snaps/can't be removed, drill it out and then fit stainless steel bolt/washer/nut.