Had same problem with my rears (Mirror polished 19's - 53 Plate Coupe) and BMW warranty said NO.
They tried to say that the wheel had been repaired / refurbed and therefore it wasn't their problem. (It hadn't been but how could I prove it?)
For that reason I decided not to renew the extended warranty for the fourth year. Tossers!
In the meantime I'm looking for a company who will repair it and guarantee their work, most seem reluctant to do this.
Let me know if you have any luck?