neil,spotless,
thanks for the replies,we do tighten the locking nut....quite a lot, in fact, we now have a ring spanner with us all the time just for that reason, but the actual pole wears and so they still twist, we have had the problem aver since we got the system, even with new collars it only helps for a week or so.
the main reason for the post was to ask if anyone else has the problem and to ask if they managed to solve it. we have even tried drilling holes in the poles and pushing wire through to lock them both in place....didnt really work, so we now use the spanner to loosen and tighten the nut everytime we extend or shorten the pole...i just wondered if anyone had a better answer...or if they use a different type of pole, and have better results.
incidentally moderators....i am not receiving my automatic alert when this post is replied to