[richstant]

Thanks for all the info & suggestions, I think I may have sorted it. It occurred to me that I've recently switched to using kobo uncaged, so I can transfer books wirelessly (no old-style USB ports on the new laptop). I found that if I connect by a USB cable, then the book does get converted properly into a kepub on transfer. However if I transfer wirelessly, via kobo uncaged, I only get the epub. That's despite kobo uncaged saying that it supports kepub (and is set to prefer kepub). I could have sworn I'd tested this yesterday, and I got epub under both circumstances, but I think I must have just got myself in a mess with all the different things I tried.

I'd assumed that kobo uncaged was still using the kobo touch extended plugin in order to talk to the kobo. I assume from this that it isn't? In which case I need to install the kepub output converter, and convert in calibre if I want kobo uncaged to use the kepub?