Not sure that it is fair that there should be clear warnings about speed cameras, if there is clear guidance on the speed limit then that should be enough. A friend was caught by a mobile speed camera and he was pissed off because it was obscured by the car in front as they came up a slight...
He's a nice lad, he normally comes down to us every 6 months or so and we have a good chat about fishing, he does not strike me as the type to tell porkies. He was flabbergasted that they would do him for 1mph over. Needless to say, he does not want points on his licence or he's stuffed.
A service engineer who had a call out to my place said he got done on the M25 doing 51 mph when there was a temporary 50 mph warning on the gantry.
The letter arrived too late for him to accept the speed awareness course so he gad to take the points. Beware!