Sorry - hit "Post Quic Reply" by mistake there, before I'd finished...
So, it seems as if Calibre can't distinguish properly between collections and series data. Alternatively, I might have done something - but, if that's the case, some kind of warning dialogue would have been useful: "Are you sure you want to erase all of the collections data from your device?"
Anyway, I then decided to uninstall Calibre completely, and remove Registry entries (I tried the instructions here first:
https://www.mobileread.com/forums/sh...ad.php?t=98977 - but it didn't work: all my settings were still there when I opened Calibre again). There were three or four entries that the Registry wouldn't let me remove - and I can only assume they contain all of my old (bad!) Calibre settings, because when I reinstalled it there were all still there!!!
So, I'd be really grateful if you could let me know how to remove Calibre COMPLETELY, so that I can start from scratch - and then remember never to try and get it to handle collections data!
Again, many thanks in advance...