No, Jewelers Rouge is not the right stuff. The paste is too abrasive for plastics, you need something that's a lot less abrasive.
Try http://www.chronos.ltd.uk, look at the site map and go to 'Polishing & Metal Finishing' (can't give a direct page link as they use Actinic Catalogue which sends you where it wants regardless of where you actually ask to go). The polishing abrasives are near the bottom of the page when you eventually get to the correct page.
Chronos does take a bit of time to deliver (I've had around 2 weeks on one delivery), but I've never had any problems with their stuff. They are also cheaper than my local engineering suppliers for a good few things, and are well worth book marking.
I work at a school and we do lots of work with acrylic by hand Braso is good but better is a buffing wheel and polishing compopund (sold in a block and of various grades for metal)