A few months ago I drove past the same 2 policeman pointing a speed gun at me 2 days in a row. They were hidden on the brough of a hill, just before the limit goes from 30 to national, so I had already sped up to nearly 50 when I passed them (both times, I thought the chances of them being there 2 days in a row in the same spot at the same time were slim, I've never known it to happen before). I was a bit worried about it, waiting for 6 points on my licence, but got nothing. I have heard from many people that with the hand held guns they have to pull you over for it as the guns do not record anything but the speed, which is not enough evidence to prosecute later, so you should be fine.