MBUSA changes names of standard Mercedes colors to "suit" the USA market.
Sometimes the change verges on misleading, for example my "Desert Silver" GL color was called "Travertine Beige" in rest of world markets. It's kind of light gold IMHO but certainly is nothing like "silver."
Why not configure an ML at the UK website
http://www2.mercedes-benz.co.uk/cont...?isflipfocus=1) where I bet this color (Steel Grey) is called "Lazurite Blue."