urmm not sure with a radar gun, but i saw on traffic police once that they clocked a lupo Gti at 140mph, and chased it afterwards pretty sure your allowed 10% of the speed limit+1 so 56 is the max you can get away with, although, my brother had a speeding fine for 34mph in a 30 you'll have to wait and see, but with it being a radar gun, id have thought they would have followed you