Halfords sell a coloured T-cut and colour restorer which will bring it up well but it may not last. Red paint does seem to fade - plenty of washed out old Fiestas bear witness to that.
I agree with MoodySabre, I used colour magic on my bayliner, first time you use it it goes blotchy fear not another application brings the shine back. I have also used T cut's scratch remover on my yacht GRP hull to good effect. Just make sure you test it on a small area first.
If it is colored gelcoat, then you need to polish it with a machine to take away the faded material.
For good results you should have a polish/cut product and then afterwards apply a hardwax/conserving product.
Anyone promising to do in one go is belying the incompatible functions of polishing and conserving agents, respectively.
Elbow grease and MER polish, mirrow finish with long lasting results and once you have the shine it takes no keeping on top of. It's no Magic Wand it's hard work.