Grade 6 ESL Grammar Book

I am looking for a good ESL grammar book for teaching grade 6. My kids are very bright. About the only ting that challenges them is indirect speech. Anything with around that level of difficulty would be nice. They also need a good source of written media for their media studies class. They have read a few newspapers, but the school used ones that were aimed at senior high. They were much too hard, and incredibly dull. Any ideas?