Hey Jo, not sure if you read my thread on headlight polishing but I too did it that way, (think I finished with 2000 grit) and it turned out fine. One thing I did since in my arm chair engineering mind, I think you lose surface tension (can't think how else to put it) by sanding. I went to a shop that has done tint and pin strip work on 4 of my cars and had him cover my lights in lexan to protect them. That was the summer of 06. I haven't seen any deterioration what so ever. Haven't done anything since other then washings. Just something to consider.