My last post on this topic (same name) is at https://premium.wpmudev.org/forums/topic/cannot-install-sidebars-still-only-get-to-define-where-your-sidebar-should-appear
There is a reply from Tyler Postle there but I can' see any where I can add a reply to his post.
I'm jus not having anuy luck!
Anyway my reply was going to be"Allow this sidebar to be replaced" option is checked. When I click on Sidebar Location option the nre custom sidebar isn't insertef. I am so stuck!