So, I was having a rake around, trying to identify the length I should aim for when writing for a specific age group. Advice on word counts does not get any more no-nonsense than this, people! An agent’s blog, endorsed by other veterans of the children’s publishing industry:
Ridiculously straightforward, sensible and helpful. Check it out!
Also, if you want to check the word count of already published books which serve the same readership as your cherished opus, do an advanced search at AR BookFinder. A brilliant resource!