As for fixing it, there is one other thing you can try, and it usually works very good. However, it would involve using sandpaper, so if the material has texture, it may smooth it down a bit.
1) Wash the panels with soap, Super Cleaner, and/or an IPA solution.
2) Sand the areas with 400/600 grit sandpaper, or a finer grade if you prefer to minimize the texture from being removed.
3) Rinse with water, then thoroughly dry the surface
4) Apply the Plastic Restorer, and let it penetrate for like 20-30 minutes
5) Wipe it off, wait another 10 minutes
6) Wipe it off again to ensure all excess is removed.
This sandpaper step usually works really well to open up the pores and allows the restorer to penetrate the material better.
But of course, if you don't want to do all that, just stripping and painting it will always work the best.