It is I who was daft, which is why I edited my post.
I missed the change of page. I believe you CAN add author and series prefixes, but in the custom column instead of in Kindle collections. The doing of that is beyond me, though. Tomorrow's my 10th anniversary, and so I'm having a tech free day, but if you get no answers before I get back I'll have my brother work on something for you. Just in case, what did you want for series and what for authors?