Background for question (2) :-
The bundle for the entire village went into the stream and ran along under water for a very short distance, quite near to my house. High up on the moor this happens again in a few other places, and in many places the cable bundle is not buried, it just lies on the surface by the roadside, in a rocky shallow ditch which will only fill with water when there is heavy rain.
So for two or three miles a certain fraction of the length is under water whenever it rains. Many years back, rain used to mean water getting into the outer insulation, and there were also vulnerable joints in a couple of places. BT had even run the cable over stony ground over which vehicles were driving often, thus grinding the bundle to a pulp constantly. Over ten years ago, someone with a brain replaced the whole lot (I suspect), started again, joint-free (or at least almost so), and buried the short section that was being used as a doormat.