Its pretty easy to miss a sign, a thirty zone has no repeaters remember, so if you missed the first one you would never know the limit had changed.
And remember the reason a 30 zone has no repeaters is because the street lighting is there to act as a repeater. If its not a road that has the correct street lighting, as a non-residential street like this one wouldn't have, it isn't allowed to become a thirty zone unless the council apply for it, which is what they didn't do in this case.
We can't have the authorities not following their own rules, or making them up as they go along, I'm suprised you disagree with this, normally its something we both agree on..
No we can't have authorities making rules up as they go along, which is why I agree that it's right that the penalties are taken away, but equally it's not right that 3,500 drivers have broken a speed limit (I'm willing to wager that a good number of those were locals and knew the road and were more than aware of the speed limit) to the extent that they've set a camera off, and have walked away scott free.
I stand by my original thought. let them off for this time, since there was a balls up with the planning procedure, but if they get caught again then whack the original charge back on them, since they obviosuly didn't learn from their very, very fortunate escape.
I'm a pretty laid back, leniant sort of person as a rule of thumb, but speeding in a 30mph zone is strictly for [censored] idiots
(and incidentally, some 30mph zones have repeaters, and 30mph road markings too, in both built up and rural areas)