Adamski, trip to Halfords to buy specialist headlight renovator, but none available, so chatting to the guys there, they pointed me towards a caravan, perspex window renovator.
£7.99 for a small bottle, but not much used for both headlights.
If peeps agree it's an improvement, i'll post a pic of the product.
I think it worked (two applications so far) and more to come.