Many of the publishers have some really interesting material which you might find useful for specific topics. Some also have resource books with ideas for projects.

http://www.redhouse.co.uk – Wide range of fiction, non-fiction, activity and resource books.

http://www.collinseducation.com

http://www.nelsonthornes.co.uk

http://www.oup.co.uk

http://uk.cambridge.org

http://www.mcgraw-hill.co.uk/

http://www.macmillan.com

http://www.folens.com/ – check out the Belair series for ideas for projects for younger children.

http://www.thebookpeople.co.uk/ – Reasonably priced boxed sets of fiction and non fiction. Also good for activity and resource books.

http://www.cgpbooks.co.uk