Book bought from Apple Bookstore formatted incorrectly

I just bought a new book via the Bookstore and when’s I tried to open it I got the ‘formatted incorrectly or not in a format that Apple recognises’ error message (prompting the obvious question: why would Apple sell a book whose format isn’t recognised?!)

I’ve tried removing and re-downloading but to no avail. Any suggestions gratefully received!

cheers,

Steven