On dropping the ladder feed down, I was able to get a better look at my ladder spacers, made from plastic milk bottle material. Someone suggested the UV would have affected them, but they did appear to be fine from the ground looking up.
They have in fact degraded quite badly, so I'm wondering about possible alternatives. An obvious one which came to mind, was 2L clear plastic lemonade bottle material cut up. Will this be UV resistant?
Idea is to cut it into strips 2"(H) x 1.5"(V) with two holes pierced at each side. Cable (vertical) x2 is then threaded in the upper hole, back out of the lower one, so these spacers stay put where they are placed on the cable, like the rungs on a ladder, hence the name 'ladder line'.