First, you'll want to double check your bike's color. In the US, for the 2002 model year, the Sprint ST was available in British Racing Green. Aston Green was available in 2003 and 2004. It may have been different in the UK, or you may be going by registration year (which is not useful for determining things like paint color, parts requirements, etc.).
This might help if your bike is BRG:
Other than that, Triumph has taken down their page with the codes on it. That may not be such a bad thing, as most of the people who tried to use the codes reported failure to do so. Lots of people have had good luck getting their bikes matched by scanner, and the scanner will do a much better job if there's been any sun fading. Some colors, like Lucifer Orange or Pearl White, really just can't be scanned, but neither of the greens your bike could be should be a problem.