OK many people might already know about this site but I just found it it is
Youu join for free and list the books you would like to swap, once this is done you can browse their library and when you see a book you would like you offer to swap it for one of yours. This is the best thing I’ve seen in awhile. After posting 5 books I was instantly offered swaps for 2 of them.
They even have parenting books, I think a parenting one would-be good to look at to get some ideas on handling Wills tantrums. Anyway it is cheaper than buying off amazon as you only pay for your books to be sent out so you end up paying around £1.
Want a bargain!!!