DGS approached by stranger

I'd like to know as well as something similar happened where my daughter lives last week.

Do you have a community policeman in the village, Whitewave? I think that would be my first port of call. Presumably the pice have been notified anyway.
Also is there a Victim Support in your area who could help your DGS? Even though he wasn't physically hurt the experience has obviously made him anxious.
My DS was assaulted by a group of younger boys once, and the woman from VS who came round was very helpful.

Police.

It seems to be on the increase as there have been 5/6 reports of a man in a white van trying to stop girls coming home from school during the past 2 weeks the girls are now going home or to the bus in pairs or being collected.

In all cases of children being approached by unknown adults - especially if it's happened to several other children - the police ought to be made aware of it. Seriously. How would the parents and children feel if a child were subsequently to be abducted?

Sorry - to answer the question in the OP, I believe that the police would make their presence visible at times when children ar going to or leaving school and keep an eye open for the potential offender as described by the children. He may already be on the sex offenders' register.

Definitely talk to the police - better safe than sorry. And GS will need lots of support and some pretty grown-up conversations to help him understand the risk, but also to get it in proportion so he can continue with his life with confidence.

whitewave, I couldn't work out whether this man lives in the village, or was driving through it. Asking teenage boys to help with the car/computer/what a nice dog you have etc are classic ways of beginning a grooming process. Whether he lives in the village, or was driving through, it definitely need to be reported to the police. When one of our daughters had a similar experience, the policewoman who visited told us there had been a number of similar reports in the past couple of weeks. She questioned our daughter very sensitively, and gave her a lot of praise for the way in which she'd responded when the men asked her to get in their car.
Report it. Your grandson is a good age to provide helpful information to the police.

Just to echo what others have said: the police should be told. If everyone reported any suspicious activity like this, the police can then plot the reported sites and see if there is a pattern to where these men are likely to appear.

If you know there is someone hanging around, discourage youngsters from going out alone but to always be with a group of friends.