I do speed on Motorways I have to say, as the speed limit seems ridiculous nowadays, but try very hard in built up areas to remain within the limit - sometimes it does creep up a bit without you noticing - so will be using my new found speed limiter more in future!
I have only been 'caught' once - it was a planned manoeuvre as I knew the A697 between Scotland and England well in those days (the 1980's) I lived in Scotland and my Dad was dying in Yorkshire, so made the trip every fortnight .... as you get closer to the A1 at Morpeth, there was a long long hill that you could see the top of for miles once you got around the corner out of the last village, and there was a caravan approaching the bottom of the hill - this hill was the last overtaking place with a crawler lane before you got to Morpeth, so in my sporty black XR2, lights on, I sped up in order to be able to pass the caravan on the crawler lane before it got to the top. I had almost got to the caravan when a man in a peaked cap jumped out from behind a bush and zapped me with a radar gun! I pulled over and was expecting a Fixed Penalty Fine, but it appeared that because I lived in Scotland, I had to go to Court ... so at what is probably one of the smallest Courts in the UK? , Rothly in Northumberland, I was done for doing 79.62 mph on the A697 which cost me £60 rather than the Fixed Penalty which I think was £20 - grrrr!