Just looking around for potential answers it has already been in once, but found no direct issue (bar the fact my front tyres are wearing on the outside edge and slightly feathering it is in for a KDS on Wednesday).
is a light whistling (and when I mean light and i mean really light and you struggle to hear it) over 30mph to the legal UK limit
...tried brakes nothing there stuck etc., wheel bearings nothing rumbling or unduly warmer than the other side etc.
Naturally as said above BMW can find nothing wrong with it at the moment.