I've just ordered and received the Kaplan ICB books for Level II and they seem good. I think (?) these are the same books that you can purchase through the ICB shop.
I am self studying though having had quite a bit of experience in accounts and book keeping - so I can't really comment on how easy I would find their explanations if I was starting with fresh eyes - but they seem pretty straightforward and detailed.
Are you self studying or taking a course ?
The other thing that I noticed is that if you are able to access e-books there are a few free e-books on Amazon published by the Open University from their accounts courses (eg Introduction to Book keeping and Accounting).
The only other book that I have seen recommended quite a few times is Frank Wood - Business Accounting. Fairly expensive, but you can get older, second hand editions fairly cheaply.