How or why you managed to get it in the first place is probably as much of a mystery to you as it is to me Paul. I did search to see if there had been any reporting of recent changes to the way French TV is transmitted, but no luck thus far.
As far as seeking to get French TV is concerned, it is a fairly common wish with many, many forums and blogs out there to 'help', but as you say there are those around who actually know what they are talking about. They will no doubt look in soon enough.
There is this...
http://www.ddelec.com/french/french.htm