Hi MUZ
My E70 is extremely noisy from the front end too - the car has been in and out of the dealers many times and even had the front diff replaced, but still have a hollow roaring noise coming from the front end - there has been many postings on here and other X5 forums regarding the same problem and the common factor is 20'' Bridgestone run flat tyres - my dealer let me drive 2 other X5's and they are all the same and when the car is lifted off the floor on a ramp and driven up to 60mph the noise has gone - hence proving its a tyre problem.
Hope this helps
Nick