Alex
I used Blackfire Polish, followed by Blackfire Sealant.
But I think the most important thing is to get the prep right and make sure that whatever polish and wax your applying is going onto a completely smooth surface.
If you use Meguiars Quik Clay kit (availble from Halfords) that will make the surface like glass, then you can follow with Polish and Wax or just Wax. Most Waxes give a similar result if applied and removed correctly, the difference is mainly in the ease of application, removal and longevity. Meguiars Gold Class is excellent for Black as is Turtle Wax Platinum which is also easier to remove as well.
I have heard good things about Autoglymn Ultra Deep Shine but i havent tried that yet
, so cant really comment.
Cheers Rob