I don't know what it was, as it stopped in Barcelona and wouldn't connect in Italy, even though I had specified that I would be travelling to Italy, so it was meant to work. When we crossed the border into Slovenia, I thought I'd give it a go and see - lo and behold it worked! Glory be to the phone fairies.
Perhaps knowing that I was soon to be in Italy, it decided to prime me by ceasing in Barcelona a few days early, and now that I'm back where it wants to be, and will be for a while, it has decided to work again.
So, on that basis, I am hoping that it will continue to work wherever I am - and to be on the safe side, I will not turn it off until I next board a plane (which will be when I'm on my way home).
I know it's not much, but to me it's good news, as it not only saves the euros having to buy a new sim-card in each country, but more importantly it saves the time and hassle of having to do so.
Little wins ...