So I've just had a quick look in the manual.
Seems there is a button to deactivate the sensors but my car does not have that button. The button also disables the rear view camera, but I don't have the camera.
So my 'button' to turn them off is the start/stop button! No biggie, can cope with that!
Current: 2013 F30 320D M Sport AW, 403M 19", Bi-Xenon, Black Leather
2005 E91 320D M sport, BSM, Twist 230 19's, Lemon Leather. Death by Swirl Flap
2002 E46 320i M Sport, Convertible, Titanuim Silver, 19's, Xenon, Black Nappa Leather
1998 Lotus Elise 111S, Black