I tried to get some paint mixed at hellfrauds, (they were nearest) a couple of years ago for Dad's XJ-S.
I went to them armed with car's exact model, year, complete chassis number, Jaguar colour name,(Silver Birch) and maker's colour code taken from the car itself, confident with all that info even they could'nt cock it up.
I think you can guess - those tw*ts said 'Certainly Sir' and then came with something greyish only slightly close and insisted I'd got it wrong and that it was really called 'Silver Bark'.
I just went to a proper bodyshop instead - no probs.