Aye, the local constabulary are likely to act rather faster than trading standards, after all if he hasn't traded TS can't touch him.
The Police on the other hand can look up the vehicle reg, see if it matches the vehicle description, keep an eye out and ask lots of questions when the find him, especially with the amount of information you have got.
A good questioning from the Police may just put him off "working" the area. He might just be a dodgy builder but distraction robbery or casing a place to return later are distinct possibilties.