a mate of mine was driving yesterday m60 …approx 15 30ish
when bang hole in passenger side front window
he pulled up pretty sharpish managed to get onto the hard shoulder…
assessed the damage …checked pulse etc etc then called the police
result …caught them
will let you know what happens next…
They will probably have to sit down in a dark room and watch a video, then get sent on some kind of course because they had a poor upbringing.
Dont hold your breath, some do gooder will have a perfectly reasonable excuse why they did this 
why not chuck them off bridge and save time 
hope your m8 is ok 
Was this on the M602 mate because my mate had his car done about 1520 on the M602 and I can let him know the police have got someone!!
Could be a double result?