The reality was that I was told to call them as soon as we had installed the new modem, to get them to reconnect to it. They don't come and install, they just send it to you by UPS.
this involved 6 phone calls to India, as they evidently had a network problem ther,e which prevented the messages getting through. They asked me for the MAC address of the modem (which was frustrating as it was written on the bottom of a modem stood on the top of a PC under a desk, and I'd just had a dental operation, and bending down was not what I wanted to do right now...)
So, this morning, 'er indoors phoned them again, and their network was working, and we are back online at home.... what a lot of hassle...
Next problem, that useless HP K5400 printer.... I think its going back...