Plexus Plastic Cleaner is an amazing product, it's the best there is for cleaning the rear window on a convertible top but it is very expensive at £24.80 for the small 7oz can.
I used this stuff on my TVR rear window and the results blew me away, the 7oz can lasted about a year as you need very little of the stuff but it's still a lot of money for such a small can.https://www.ebay.co.uk/itm/30356757...p19vU-QIVg-vtCh1vFQcFEAQYAiABEgKIW_D_BwE
I'm told Clear View is the same stuff for close to a quarter of the price as you get 13oz for £14.00, but I haven't tried it myself.
If its as good a Plexus you'll be amazed at how clear it gets the rear window, I'd still use a light polish first to remove as many scratches as possible first but if you them apply Plexus the results in my experience are a better than new finish, the Plexus not only cleans the window better than anything else it also seems to nourish the plastic so it folds more easily.
If you try the Clear View product please let us know how you get on with it, if its a genuine Plexus alternative you will not be disapointed