I travel up and down these roadworks quite a lot and have noticed since this law change HGV's are no longer doing 54/55 mph and the majority of them are now doing 49/50. Maybe there is no 10% tollorence anymore.
The law hasn't changed. It is a change in the sentencing guidelines. There is no reason to expect a change in tolerances. I haven't seen any change in driver behaviour, not that it means more than diddly sqwat.
Of more interest is this effective ban for doing 33 in a 30 area with nothing significant missing from the story. 1.01 on something significant missing from the story.
FWIW I try to always keep at 30 or below in 30 areas (childhood friend is no longer with us and I hit a predestrian when doing a bit less than 30 and have seen how much it shook them up. I do the just a bit over everywhere else, and have been known to do a bit more when tilted.