BMW X5 (2007 - 2013) 4.4 xDrive X5M 5d Auto Owner Review

I received my New BMW X5M on 8th Jan and within the first 2 weeks I noted that a constant annoying sound comes from the front Dashboard. I hear this noise even when the car is stopped at signals and engine not running. Typically this sound disappears at speed above 30 mph. Maybe the noise is overtaken by the outside noise and you don't notice it. If the drive the car in City i get headache and also tend to loose concentration as I am unable to take my mind away from this noise. I contacted the dealer and dropped the car for check up at Cooper Croydon. They have comeback to me with a reply that this is Characteristic of the car as they replaced some parts and the noise still exists and they have compared with another X5M and that car also has the same noise. I spoke to BMW UK and they call it as Characteristic of the car but also claim that engineers are working to find a solution for this but at the moment there is no solution. Also they mentioned that only some of the X5M have this problem and they are sorry that my car has this issue. I haven't picked up the car from the dealer yet and have communicated to BMW FS that I am rejecting the car as BMW hasn't taken a responsibility that they would fix this problem. They are expecting me to continue driving the car as they don't a solution for this issue. Going crazy with the purchase of this dream car