That seems a bit expensive even without any discount. Discs and pads are £299 for the 530d and you only need to do the discs roughly every second set of pads. Discs are replaced purely on condition and minimum thickness.
As the E60 isn't included in the BMW 'Value Service' plan then sadly there is no fixed price for discs and pads on an E60 - its down to the individual dealer what they charge
