i had my windscreen bricked a couple of years ago, dont know if it was a windy, i did argue with a few builders that week who were shouting sexist comments at my wife, so it could have been them?
even if it was windys, i was only out of work a day, and £75 down, so just keep the van now in a safer place.
my mate who owned the round before me had his tyres slashed by a windy. not a nice experience for you though, makes my blood boil when i hear storys like this! very tempting to do a tit for tat war, but that will just escalate until one of you gives up. best to get cctv as advised and inform old bill every time. dont let them win, keep going, and take precautions, he will give up eventually.