I've been playing with Calibre, and spent last night getting all my book tags updated, what an awesome program!!
I have the Kindle Collections add on installed, and have created my collections (using 'series' as the collection item). I show them in Calibre, but when I tell them to upload to the Kindle and reboot, they don't show up on the Kindle.
Edit: I found a thread here https://www.mobileread.com/forums/sho...=192561&page=8
that addresses this. ::bonk:: Search before I post! Anyway, reconverting and uploading again with recommended settings from this thread.