Not quite sure which 'beeps' you are referring to here. I think you may be hearing the fairly loud, and higher pitched, beep that is warning you about the latest HADECS 3 cameras, and not the excess speed warning which is adjustable. This stands for Highways Agency Digital Enforcement Camera System 3, generally installed on motorways (pole or gantry), and painted grey. They are smart, and detect you approaching, as opposed to the old systems which detected you when you pass (very often causing people to slam on their brakes!) Often deployed in variable speed zones. The beeps will start approx 30 seconds before you reach the camera, and cease immediately after you pass it. I have just covered 200 mls of motorway driving and very much appreciate the warnings as we all give the occasional 'squirt on the gas' without even realising it!