Just thought I'd add to this thread now as today I used the Meguairs headlight restoration kit "plus" on my Zed.
It's their new version of the kit which includes 4 grades of wet & dry on two handy little pads.
Link: http://www.ebay.co.uk/itm/MEGUIARS-ONE-STEP-HEADLIGHT-RESTORATION-KIT-BRAND-NEW-IN-STOCK-/160846872489?_trksid=p2054897.l4275
Firstly I used the kit without trying the sanding pads ~ this gave me a good finish but there was still bad fogging on the corners of my lights. So I manned up and used the sanding pads.
It was worrying at first as obviously you are adding scratches at first when you use the pads. In fact after using the first grade of pad and wiping off the water you can see it totally hazes your entire light cover. I persevered with the sanding using one grade at a time, lots of water and following the instructions using one side to side, then the next up & down and so on.
Once I had completed the sanding steps I then went back to using the mop and PlastX ~ this was when the magic happened and finally my headlights look "almost" as good as new again. Very happy with the results and wish I'd tried this in the first place rather than the other products I had tried which where useless.