Don't think it will have a colour code as such as they are not painted directly from Honda Japan. They were commissioned by Honda UK and they are a paint job through Spray Bay immingham I think.
Just checked one - it says black :- https://www.vehicleenquiry.service.gov.uk/ Vehicle colour BLACK Surprised they are registered as that? As mentioned above, they should have the current colour in the log book.
That will prob give insurance companies a get out of paying out as details incorrect if someone was makin a claim!