Just found this thread but obviously way too late to help Ruby 2, although the question has been answered thoroughly. That said my experience may help a Torch Red C5 owner at some stage in the future.
I needed a spray can to match my '02 Torch Red and went to Halfords, as previously recommended on here. All they needed was the OE code and payment with order. Only a few days to wait and the can was ready, the colour match was as perfect as you could get from anyone. I also got some discount using my trade card, again as previously recommended on here.