hmm, well i cant find one in halfords so that doesnt help.. but...
3M do some good ones!
I used to do a lot of it, used .. in this order
3M Fast cut plus
3M Perfect it
3M Anti hologram
.. then of course a good polish
Each one has a colour coded polishing pad for a machine polisher that matches the bottle top, i don't know what size bottles they do, we use 1L bottles which are pricey for all three but they are very good, i used to use them to restore/prep cars at a dealership, correct foam pads are a must though, personally i would phone around a few paint suppliers and see what they can supply, dont get mixed up with things like the classic G3, some are very harsh and not made for making it "shiney" you can get away with cutting it back with perfect it and then polish, anti hologram is more for when the fast cut has gone deep and its left marks. a good polish will do that.
Alternative is to use t-cut with a machine, then polish. Unless your paint is very dull and surface scratched, it will probably do the job just fine.