I had a problem a couple of years ago with kids playing next to my flat we live on the ground floor, they kept kicking the ball (by accident) against my windows, so i went outside, and asked them nicely please could they play on the next field, which was a 1 minute to walk to, no flats nearby, and a bigger playing field, and they did, so i would just ask them nicely. Calling the police is a little over the top if it is only kids doing normal kiddie things.