iBooks pre-order issue

Hi all,

i recently pre-ordered the iBook "Hellfire" by Chris Ryan, this was scheduled for release on 27th August.

When I now attempt to download the book the screen just continually loads but will not download the book, when I search for the book independently of my purchases it does not appear at all, even when I search for it it seems to not exist.

Any bright ideas gratefully received....

Dan