Polli; if the books are sideloaded then, series info can easily be handled via calibre if you use it to xfer books.
You need to setup a "Metadata Plugboard" in calibre (Preferences | Metadata Plugboards).
What I use is the following:
Code:
Format: ePub
Device: Kobo
Source Template: {series:re(([^\s])[^\s]+(\s|$),\1)}{series_index:0>2s| - | - }{title}
Destination Field: title
What this does is for books WITH series data, prepend the title by an abbreviation of the series name, followed by the number of the book in the series and the title.
So for instance,
The Lion, The Witch and the Wardrobe book
2 in the series
Chronicles of Narnia shows up on my Kobo as
CoN - 02 - The Lion, The Witch and the Wardrobe