Have you considered primary upd8? Not a SOW but may have some useful resources that you could use. I am surprised that there are not more science resources available for KS1-2. As a writer/editor of KS3-4 resources, I would be interested to know if there was demand for good quality, affordable KS2 science resources. This is something that I have been considering getting involved in starting up for a while. What do primary teachers think?