This is the problem, I can't remember the last time I seen any speed enforcement in 30 zones. Most of the roads up here are winding country roads with multiple tractors elderly driving slow with their nose glued to the windscreen and just some bad drivers. There are few places to safely overtake and where the safe places are ie big open straights they build a special layby and plonk these camera vans on them.
The A90 Dundee to stonehaven dual carriageway has average cameras now because six people have died since 2014. The fact that there are very few flyovers a tractor/ truck and trailer can still pull out in front of you , sit in the central reservation with a trailer blocking both lanes while making sure it's clear to go from the other carriageway is completely ignored.
Literally drives me nuts.