<< Being heavily fined for being just over a speed limit is draconian in a civilised country. >>

Not sure exactly what you are suggesting - that the fine should be proportional to the excess speed ? Well, that already happens to an extent, I think. Or "well, I wasn't much over, so let's call it quits" ?

Once it is accepted that speed limits are necessary, the speed has to be fixed and then complaints start from those who are caught 'just over' the limit. A safety margin is already built into most speedometers so that they over-read, and fines are based on actual (true) speed. The radar-operated displays now common on our roads seem pretty accurate, so there is little excuse for genuine offences. People really complain about being caught, not for speeding as such.

I haven't seen any speed camera vans hiding themselves away. Round here they're in full view. One regular spot is on a bridge over a bypass (not monitoring the bypass) and can be seen for at least 400 yards in either direction. This is typical for camera vans in Gloucestershire.

Yeah, what usually happens with rules enforced in this way, it is presented in a way that is good for people which to an extent is true because we can all agree speed limits are a good thing. But at the same time they are constantly dreaming up different types of parking fines and maybe changing the speed limit in places that aren't needed to the same extent in order to make money and not really concerned with anything else, like Sammy1 said speed camera vans hiding themselves or even things like yellow boxes, all designed to make money.

Being heavily fined for being just over a speed limit is draconian in a civilised country.

Say in a 30mph speed limit how fast should you be allowed to drive without being fined?