Well, after boasting about my magnificent 2.4Mbps download speed, I went downstairs last Thursday morning to find that the internet (and hence phone) had disappeared. I went to my friend's house round the corner, the one who had helped me last October, and asked her to help me again. She phoned up the SFR "help"line and the first thing they want is a mobile number. Trouble is that their mobile was out with her husband and so she couldn't go round to our house immediately.
The upshot of all this is that on Friday, yes a day after, SFR got back to say that they would get on the case in 48 hours. So, as they don't work weekends, that meant Monday. We leave on Tuesday so chances were that meant no internet for the rest of time down there.
Surprisingly, on Monday morning the indicator lights on the modem changed to green and we were up and running again. For all of half a day's use! I'm certain that if they'd got their fingers out it could have been fixed before the weekend. SFR, I hate them.