[geertm]

The new WH Smith e-book store is part of the regular WH Smith website.
It seems like the new store is completely seperate from the old one. I had to register a new account.
I was hoping that geo-restrictions at the new store would be less severe than those at the old one.

There are no geo-restictons mentioned in the e-book information. I first registered my account with my Dutch address and bought some books that are UK only in the old store. I could not proceed to the payment page without supplying a UK address.
Than I registered my account with a UK address. Bought the same books again. Now I could proceed to the payment page. I used the UK address with my Dutch credit card. Payment accepted. Received order confirmation by e-mail.
After waiting a few minutes the download button was available for the books in my account. Downloading went without a problem.

So for the moment it seems using a UK address registering your account and as billing address for your credit card is enough to circumvent geo-restrictions.
There seems to be no IP-address check, and no verification of the credit card billing address.