I'm afraid that this is pretty much a wheel off job, although it might be possible to do it with the wheel on, you'll find it a lot easier with the wheel removed. I started doing it with the wheel on, but ended up taking the wheels off part way through!
Once you've jacked the car up and removed the wheel, make sure that the area that the mud flap goes onto is nice and clean and dry. The mudflap has a section of double sided sticky tape which needs to bond onto the wing to make a good fit.
You'll see 3 little plugs on the plastic insert (circled below ), you need to remove the bottom 2. To do this push something small into the centre to push through the small pin (don't worry about where it goes - you wont need them and they'll end up falling out themselves), and then lever out the plug itself.
Now under the sideskirt there is also a plastic screw thing with a torx head, this also needs to be removed. It unscrews, so unscrew it!
Now you can test fit the mudflap (don't remove the backing tape yet!), and you'll see that the two upper holes on the mudflap can line up with the two plugs you've removed. And the little notch on the other side will fit in the gap between the wind and the side skirt.
Have 2 of the replacement plug/pin things ready and remove the backing tape from the inside of the mudflap. Now slide the mudflap into place and use the 2 plugs to hold it in the correct position. You can press where the tape is to make sure it sticks to the bodywork. Now push the pins until the end is flush with the head of the plug. And then screw in the large plastic screw underneath - don't overtighten, it's only plastic!!. (The mudflaps come with a large push in plug which I think you could also use underneath, but I decided to use the screw in one instead!)
Now the final hole on the inner wing needs a screw into the plastic. Take one of the black screws that came with the mudflaps, and screw it through the remaining hole! You don't need to pre-drill it as the end of the screw has a drill type end to allow it to cut through the plastic.
If you've taken the wheel off, now go and give the inside rim of the alloy a good clean!
Put the wheel back on, lower the car and admire your handiwork!
Do the other side in exactly the same way!
