Trinity, thank you for your reply. The magic box was already deleted, but it seemed that yesterday, whatever I did, these items wouldn't depart from Unassociated. I know they were not really causing a problem there, it was more a case of me wanting them out of the way so I could see better what I was doing. Doing better today, although I am still getting this "Sorry to keep you waiting" message, also when clicking Create New Listing.
Now I have the problem that some of my migrated items are in the wrong category - I've attempted several times to change it, apparently without success, but maybe it takes a while to propagate through the system - anyone know?