Re: Get the basics right first.
... all down to the old ally cabling that no-ones interested in renewing as it would mean re-wiring the entire estate she lives on
I feel your pain. At a previous job, we had a site on the Isle of Wight which we fairly quickly found out was served with a lump of alli cable somewhere down the lines. We had repeated line faults, and it seemed we seldom had the full complement of lines working (voice POTS lines, fax line, one Kilostream leased line and ISDN2 as backup for the leased line - yes, this was some time ago). It was probably the number of faults on the leased line that triggered the replacement of the trunk cable - the SLA on that probably meant that multiple faults triggered some reporting within BT. Once they replaced that length of cable, everything became stable and reliable.
BT will take the view that "if it aint broke, don't spend money on it". So unless they start getting a lot of line faults which are because of the alli cable, they will not do anything about it. Of course, it would be terrible (wink wink) if a car had a mishap and petrol spilled into the ducting and melted the cabling in the ensuing fire. Or if some corrosive chemical (slightly salty water doesn't mix with steel and alli, wink wink) found it's way into some of the supposedly sealed joint boxes and made the alli turn to white powder. Of course, I couldn't under any circumstances suggest any form of vandalism, that would be illegal and immoral.
Oh yes, and don't mention to any of the dodgy characters in the pub that alli has a good scrap value either.
Biting the hand that feeds IT
