I used Chipex recently on something very similar on my car.
You'll need:
Either a Chipex kit or just the paint, solvent, brushes, and the blending cloth(s).
2000 grit sandpaper.
Compound and polish and corresponding pads.
Steps:
1) Lightly scuff up the scratch, with the sandpaper this is to remove any parts that are sticking out and to make the paint stick better,
2) Use the Chipex kit/ paint according to their instructions.
3) Put some of the chipex solvent on the sandpaper, and lightly scuff the paint again. This is to remove and level the touch up paint with the regular paint. If theres still a Little indent/dimple, repeat step 2.
4) Then use the compound. I used meguiars 105.
5) Then polish. I used Meguiars 205.
I had some scratches on the rear black wing and on the boot lid from sloppy loading, and they're practically gone. Hope this helps.
Note: You don't need to use Chipex. Any paint/chip repair kit should work.