the rep is talking out of his rear, like noel both my minis had white/cream interiors the were excellant and easy to keep clean. and i was offered black or brown.
even if its a cost option motability have no say in what you choose.
if available in future i will always go for a non black option.
if i were in the market for that model i would go light its too big a car for all that black would depress me terribley.