While trying to log in to my Apple account to see what was happening on iBooks this morning I somehow ended up creating a new account which has left me locked out of the original account! After a lot of searching I found a number to ring and spoke to someone who seemed to know what to do. They sent me an email with instructions to clear the cache and browsing history, which I did but the problem remains.
Just had a reply back by email and the problem has been “escalated” which sounds hopeful. 🙂