Thanks for the explanation. Was as clear as mud before, apart from A & A telling me roughly where the fault might be located.
I do have a wired telephone, but I would need poor Mrs Weaver to unscrew the AAISP shop plain RJ45-only faceplate to get to the test socket. I might be able to find a volunteer to help.
Mrs Weaver's hands are worse than mine.
Engineer has been booked by A & A. He or she is not coming to
me though, apparently. They pointed that out because there was no issue about me having to be in at a particular time, presumably.