There may well be a variation of black surrounds available for Cooper/One but as far as I know, they only fit the S and Aero S bumpers.But the Chrome & black surrounds both fit the Aero bumper....the plot indeed thickens! (See Scoobydoos Cooper)
Jo, you need to specifically ask for the Cooper D aero grille (although it is the same as the S) as the Cooper/One grille is a slightly different shape to the D and S grille. The Aero grille can certainly be fitted to the D and I think you can use your exisitng chrome surround. If in doubt, ask the dealer if he'll give you a refund if it doesn't work - afterall its the least they could do considering your purchasing a highly specced car from them.