I haven't a clue Pegasus, but I would imagine it was single glazed in a warm country.
If you had read my post, you would see that I had just said that I believed that Gerry and Jez would have been chatting in hushed voices, cos Jezes little one was asleep in the pushchair. They were 10 metres away and out of sight. Even with the window open I doubt that anyone would have heard in those circumstance ... and certainly not through a closed window, single or double glazed.
IMO
If I can remember, I'll try to nip down for a peek.
I have been in perhaps 15 to 20 properties in Portugal and Spain and all bar 1 had double-glazing.
It is sitting in the low 30s in the shade outside at the moment, but the double glazing means it is low 20s inside. In winter, it works the opposite way. If it is, say, 13C outside, then you want something that keeps the heat in efficiently.
Kate writes about checking the patio door to see if wind was going out that way. If the window was open, then checking the patio door was a bit pointless.