Clear over base..respray or just ignore..
A good flat and polish might do the trick but you need to know what's what with that.
Try a good cutting compound like G3 or similar first..ask at a good car spares shop or auto paint supplier.
http://www.ebay.co.uk/itm/Farecla-G...473005?hash=item19e27492ed:g:KmMAAOSwc-tY3p-I
I use that everyday, it will not work on that roof. A base and clear would work well if stripped back to bare metal first, expect in the region of £250, in fact most often for the trade we would expect £500 for a quality job.