Went up to Halfrauds and tried to find a paint to match the frame on my FZ6 without luck I can find ones that look similar, but I'm not sure the finish would match and it would probably annoy me more to have something almost, but not quite right and I really don't want to have to repaint the whole rear end...
Have you tried here ? http://www.rsbikepaint.com/en-gb/colours.php?setlocale=true
That's what I'd do - getting a colour that's "close enough" will do, as long as you paint the whole thing.
If you've got the time to let the paint cure for a couple of days, I'd give it a final 2 coats of Halfords Heavy Duty PU Clear Lacquer to finish the job off. I've used it when I repainted my frame, front mudguard and my fork sliders and it gives a deeply shiny and durable finish - but if you put it on before the paint has gone off, it crinkles up something rotten (don't ask me how I know )