Where/how can I repair my plastic rear screen?

[kapadiy]

I have a small tear or cut in the middle of my plastic rear screen. It's only about a centimetre long and does not let any water in, but I was wondering if anyone has managed a repair.
I was thinking of some sort of plastic weld if it exists.
Also has anyone tried Hindsight Plastic Rear Screen Restorer? Is it any better than the Renovo Window Polish (I've not tried either but tempted to give Renovo a try first as it's only a fiver).