I'm fine now, thanks Glenda.  I think it was more indignation than anything else and concern over what could have happened if one of us had been standing behind the window at the time.  Although, from outside, the window appears high up, inside it isn't, due to different floor levels.  If they'd picked one of the other two windows along that side of the house, they'd have stood a very good chance of hitting one of us as we use those rooms most frequently, especially the kitchen where I'd be standing right behind the window.  There's no way they could see if anyone was by the windows because of the tinted, mirrored glass and net curtains.

Just got to very carefully hoover up all the tiny, very fine, bits of glass that sprayed all over the settee now and wait for someone to appear to fix the window.  Meanwhile, I guess I could look into having a sub-machine gun mounted on the balcony.  Very tempting ;D.