We have got used to the lax enforcement of speed limits in some parts of the country because differing attitudes to speed by Police Forces.
In Wiltshire, which has the lowest number of Police Officers per capita and no large areas of population other than Swindon, the Police enforce 30mph limits in residential areas quite vigorously, something I strongly support.
There are no mobile camera vans or fixed cameras, other than on the M4. Interestingly since they withdrew roadside controls and limited Traffic Police to the M4 and a few other trunk roads the level of accidents and fatalities has decreased, from almost 400 in 2006 to less than 300 in 2018.
The data is here....
http://www.travelindependent.org.uk/area_54.html Perhaps the fact that most rural roads and minor A and B roads are in such terrible condition only and idiot would speed. I believe this is a deliberate conspiracy between Wiltshire Council and Wiltshire Police.