Before I read your last post BetterRed, I had realised (silly me) that I should try Notepad as before with the pickle file (I have to laugh at the name!) So I opened it with Notepad, carefully deleted the unwanted libraries, and now I have a neat list of wanted libraries. I know I was being a bit pernickity, but when I get something in my mind that I want to sort, it really annoys me until I get it sorted - if that makes sense!
Anyway, that's it now sorted, and we know how to clear out that list (if anyone ever wants to do it in the future) so perhaps it wasn't quite such a useless exercise after all! And now we have one happy and contented Scot!
Many thanks everybody for your input even if I got a little confused at times with the conversation!
BG