The B.T. man didn't turn up, but a parcel turned up - with all the gear for the job.
I had a quick look though it, and it seems that I am expected to install the thing myself, which apparently works through
the house electric circuitry. A call to B.T. produced the reply that they should have asked us whether we wanted the
installation carried out by them, and that they would now send someone to do the installation for us - next week.
There's no doubt in my mind that reading a good book is far better than delving into the realms of modern technology.