Open the boot, lift the carpet, somewhere near the spare wheel, boot floor, rear panel, you should find a paper sticker, containing VINs/codes amongst those codes, in a larger font you should find a 4 digit combination of something like eg, LZ3Y once youve found this code, go to the "Colour Codes' section, stickied at the top of this section page, where you should be able to find a name for your colour
Thom