I agree with all of the other comments so far.
Some county libraries are starting to develop ebook libraries and so these can be read also and free.
As well as the selection here there is a young readers catagory at Many Books, which may have some suitable books -
http://manybooks.net/scripts/categor...p?code=CHI&s=1
There are plenty of UK users here meeting up with one would be a good idea or ask Waterstones to do a product demo! If you are near North Wales I can link you up with someone in llandudno.
Regards from Spain, AndiR