Funny, I just saw this thread.
Yesterday I saw two plod vans in a layby at the end of about a 3 mile straight with no side road turn offs or houses along it in a very rural area.
They really have people's sefety in mind!
I of course, travelling in the opposite direction to the cameras, flashed the 3 cars coming the other way to warn them (Iwas in my car too.)
What a waste of time, I literally passed 3 cars coming the opposite direction on the 3 mile stretch with 2 plod vans waiting to get their 'big bust'