Question Author
Wak,Twirls and Cowtipper,
Many thanks for your replies.
All good suggestions.
I don't think it was a difference in temperatures that caused the problem,Twirls, as it was a large window pane.
I think Cowtipper's lawnmower is the most likely answer but could a red whin chip or stone travel about 8 metres and over a 1'5 metre high hedge to cause this impact and then bounce back without going through the window?
I was also interested in your answer Wak, but could the stupid idiot have been using an air rifle. Would a pellet bounce off or would it pierce the glass? Never had this problem before but there's always a first time.
Thanks again to all.
A