Everyone, thank you, this thread has been much more helpful to me than I thought. Barbara, thank you for your most recent insight. That line of reasoning makes total sense, and I'll just have to hope I encounter an agent and editor who are prepared to use those arguments - it's quite easily done in my case, as there were failings on behalf of my publishers, but it just takes someone who is prepared to support me. Fingers crossed! I agree with you about traditional over self-publishing too.