I've not been caught yet, saying that, I've not really been driving a huge amount of time. But I do tend to go slightly over the speed limits in areas in which I know its safe to do so. Some of the roads by me are all labelled as 30MPH, but certainly look like they should be higher. Especially when just round the corner there are country lanes not even wide enough for two cars that are NSL... though I guess these are only a 'guideline'
What I find the most frustrating, as a new driver, are the lack off reminder signs that tell you the speed limit. If you miss one at a junction etc, then you have no idea what the speed limit is for the remainder of the road. I know there are meant to be signs to say every 500 metres or so, but on most roads, there just aren't any!
I also do that, Even if there is a 40MPH road, I'll tend to slow down to 35 regardless, continue watching the dial, and then speed up again afterwards. Like you say, dial watching is much more dangerous than going +5MPH over the speed limit.