I have about 10 different paint chips called "british racing green" (not pearl, not metallic, just plain "british racing green")... and all of them are different shades of green. And some of them don't look like what you think of as british racing green.
I've also noticed this with a few other colours that have the SAME EXACT NAME, but also look very different shades... (though I can't remember exactly what names - though soft blue may have been one of them)