@ Eric,
I agree that this situation is quite different from one I was dealing with earlier this year.
You may remember that the line had been cut loose from the house chimney but had been left dangling vertically from another building eaves and then running in parallel with a 500 W PIR lamp cable, before joining the same BT 66 box that our line was connected to. That configuration played merry hell with the ADSL signal whenever the PIR fired up.
I cured that one by reaching up from the ground as far as I could to cut the line and then spread the flat twin conductors out.
Kind regards,
Walter