Hi Ash
I'm no expert, but here is what I think, after having resprayed my car.
I assume you are respraying the whole car, in which case I think you need not worry about a match.
The paint suppliers usually have the recipe for the color on their computer, and mix it using accurate measuring.
On my resprayed car the DB180 looks original, I certainly cannot tell any difference neither from pictures nor in the flesh when comparing it with others.
What I can see, however, is where I still have the original color, this has over time become darker. So if you are talking about partially respraying the car, you would need to see a resprayer that has an optical analyser for colour, and can analyse it and provide a match with the surrounding area.
Mine is not to be a show car, so in the engine bay, I hate to admit, I have just treated rusty areas, and brushed the top coat on. No clear coat.