Have just come off the phone (to India!) after nearly 20 mins (enhanced rates), which consisted of at least 40% waiting for something to happen! The end result is that I will get another engineer to visit tomorrow - but they weren't going to do that until I mentioned the magic words " ... why am I paying for a service I'm not getting?" I suspect the modem will be changed this time, but as noted elsewhere, with more widespread problems about, I think that it is a network issue and changing modems is just the next 'tick in the box'. Like swimming through treacle ....
Will report back if any progress.
Martin.