It's not necessarily the end of the road though, as they have reverted the rights which means I could take the title somewhere else. I doubt that another publisher would consider it, but I could do it myself - I'd just need a new cover and internal layouts. That's easy enough as the artwork is based on my own illustrations. As for the series, I originally planned it as four books, three of which were written, the fourth was planned out in note form to bring the whole thing to a suitable end.
However, times move on, and right now, I'm writing a different kind of fiction. Buttercup helped to get me through a difficult time. It was fun to write and I really enjoyed the opportunity to illustrate it (which ended up more work that I realised!) but for now, the whole episode is being filed under the Downside of Traditional Publishing.