Coolaride,
Try Novus.
http://www.novuswindscreens.com.au/n_html/mainfrm.htmlThey advertise scratch removal but I have heard the glass can lose some of it's clarity after polishing.
At times the windscreen wiper blades cause scratching on the windscreen (grit trapped in the blade, faulty wiper arm, or incorrect cleaning of windscreen).
Even rear or side glass can become scratched.
And yes, Novus can remove most scratches using the most advanced scratch removal system in the world. (It can also be used on building glass, TV screens, glass top tables, etc.)
Worth a try...............
Cheers,
Craig.