ADE app on my iPad does not show my library or purchased books despite having signed in/authorised my account

Hello, just as the title says really. I just downloaded the ADE app onto my iPad 4 as I had just purchased a book through Kobo (which isn't showing in the Kobo library on my iPad either but that's another story). The book is perfectly readable on my laptop (so has definitely been purchased) but not on the iPad. Any suggestions please? Thanks very much in advance.