I've just had one of the almost daily calls roughly 20 minutes ago. I quickly said that we have no interest whatsoever and was done in a few seconds. A few weeks ago I got cocky and explained that we were considering installing photovoltaic ourselves, that we wanted to use PV roof tiles and connect up to all of the most modern storage equipment and use it as our own power system with EDF as a back up but not as a supplier. He (surprise, surprise) gave up and abruptly put the phone down. My wife asked another if he knew whether we had PV or not whereby the person at the other end of the line as whether we do or not, so she said that if they had anything to do with EDF they would actually know.
One thing to note is that instead of seeing a number, we only see an 'out of area' message, so there is no way of calling them back to tell them not to call again or making a nuisance complaint with FT.