I have finally managed to reroute the BT landline cable, which I still need for my internet (until copper connections are discontinued in the next year), which a very lazy BT man routed years ago by drilling
through the door! The linked picture shows a white aerial cable also routed through the door, with the black BT cable below it. All has gone satisfactorily, including drilling through 450mm of cottage stone wall to get the cable in the right place, and I have reconnected. I am writing this on the resulting internet connection - so far so good. However, I seem to have lost the landline phone dial tone. The cable has 8 wires - orange (which I used), green, blue & brown, and 4 white wires, one of which was connected originally. Having cut the cable to a new suitable length, I selected the orange wire and one of the white ones, having to do this at random as there are no twisted pairs, and the result is this internet connection. The white wires are plain white, rather than having a little coloured stripe spiralling around them, as I've seen in ethernet cables. Does it matter which white wire I select? Do the white wires have any effect on the landline phone?
All a little complicated by the fact that we've been having thunderstorms here today, meaning the line is tending to drop out more than it normally does (for a few minutes every couple of days on average)!