From experience, they look like 0.177 airgun pellet strikes. As you ask, why do they do it? Presumably they get some sort of kick out of causing a problem to others. Do any of the neighbours on the other side of the road have youngsters and an air rifle?
Some years ago, I was in my car, stopped in the middle of the road waiting to turn right into our road. A hand came out of the rear offside window of an approaching vehicle holding a pistol aimed at me. There was a crack as an air gun pellet smacked into the windscreen. Fortunately, I was stationary. Had I been moving at 30mph, the fright could have caused me to swerve and cause an accident. The incident was reported to the police who said that they had had several reports on the same road. The culprits were not found. Volvo windscreens are not cheap. Fortunately it was covered by my insurance.
Hope you get the windscreen changed in time for your departure to France.
Unfortunately some immature people will do anything out of boredom. Unfortunately even if they get caught all that happens is they are told don't be a naughty boy again. We hope you get it sorted before you come to France.
We are taking the Terracan & Caravan to France as everything was already booked before we got the 'Bus' (Motorhome)and we decided it would be too much hassle to change everything and risky taking an untried vehicle aboard.
So we will leave the Windscreen as it is until we get back and then let the Insurance deal with it. To be honest if we got it replaced now I would be worrying all holiday in case they did it again.
Elnagh Clipper 90.......... Real Names Mike & Hazel