I'm exhausted - been polishing my lid for 30 mins !!
OK enough of the schoolboy humour. I have been trying Greygate Plastic Polish on the lid of my deck ...
I chose it because it is cheap and have read a few good things about it. Cost just over 7 quid on ebay. It is sold as a general hard plastics / acrylic cleaner.
Results are very good, if not the miracle I was hoping for. It really does take some elbow grease to make a significant difference and I did three applications followed by polishing. From a distance the lid now looks brand new, and some stubborn marks have been removed. The lid is much more transparent and glossy which is great as it shows of the lovely bronze platter of the Source to great effect. On really close inspection there are still lots of very light swirls / marks still on there, but only if you catch them in the light. Whether much more expensive "specialist" cleaners like the Clearaudio paste can get rid of any more light scratches, I don't know, but this is worth a go as long as you have realistic expectations.
If anyone wants their lid polishing in North London I'll be happy to oblige