If I had to guess (I'm guessing because I'm not at home right now)...I'd say
that the pane is 60cm by 30cm. The inner pane had no laminate on it, and was
textured...I don't know what constitutes toughened glass, but there were
shards of glass on the carpet where the postman normally posts letters

I've had another look at the outer pane, and there is strictly no damage, no
brick dust, no pellet marks, and I didn't hear any fireworks after I was
awoken....I'm gonna have to go with the 'Spontaneous disintegration' theory
on this one...


You might like to check out

http://www.thewindowman.co.uk/explode.htm

Another bit of information. The pattern on standard texture glass is put
onto the glass, before it hardens, with a roller. The roller imprints the
pattern. This means that some parts of the glass (where the pattern is
an indentation) are thinner than the standard 4mm/6mm used in a domestic
door.

It has been a recommendation for many years and a requirement more
recently that safety glass (toughened or laminated) should be used in
doors where any part of a pane falls below 1500mm from the floor. Your
door will have safety glass in it and it will almost certainly be
toughened. I suspect that your "shards" are actually granuals,

You are going to need a new sealed unit

--
Ziggur
"S'ils te mordent, mords-les"