Do appliances in London need to be white? Or does that mean something else? I can't find anything on Google for "london white appliances", other than places to buy white appliances in London.
White goods don't have to be white, but it is still the most common colour.
White Goods are called that because they tended to have a white finish usually white formica, small appliances are sometimes still called "brown goods" because early electronics like radio's TV's etc either used wood or bakelite and had commonly a brown(ish) finish.