Go to RS Motorbike Paint. No ordering online (or didn;t used to). They like to speka to you on the phone to make sure you are asking for the right model year etc as the shades vary.
I have had the mettalic silver for ST2 and mat Titanium grey for ST4s and they are brilliant. You can get touch up bottles and spray cans, plus all the other bits you need like rubbing compaound, silicone free polish, primer, laquer etc.
I shall be going back to them for tins of red to paint a race fairing fairly soon. I assume they do it in tins for a spray gun too. http://www.motorbikepaint.co.uk/
Tel: 01226 203608
Oh yes, and thy cannot shop oversees I don't think. That questions has been asked before. Costs far too much for flamable substances.