[Loz]

There's a village on the A153 near Cadwell that has a large sign stating "Maximum speed 40mph" or very similar. There are no normal speed limit signs (red circle, white background) in evidence. The NSL applies just before the sign - this is both ways, approaching the village from the North or the South. And, there are no signs that tell you that the 40mph limit ends when you leave the village.
How enforceable is the 40mph limit here and how do you know when the NSL once again applies? I find it all mildly irritating (if not vitally important).