Let me just say that any website that doesn't use passwords by trying to do things its own way is off to a very bad start indeed. Mandatory dates of birth when they aren't selling age related goods and all I want to do is just pay by credit card is also questionable under the data protection act, 3rd principle.
"Personal data shall be adequate, relevant and not excessive in relation to the purpose or purposes for which they are processed". The wide definition of processing should be borne in mind when considering the Third Principle. In complying with this Principle, data controllers should seek to identify the minimum amount of information that is required in order properly to fulfil their purpose and this will be a question of fact in each case. If it is necessary to hold additional information about certain individuals, such information should only be collected and recorded in those cases."
So if I can buy age related goods on amazon.co.uk without telling them my actual date of birth, merely that I am old enough why do I need to hand over material for ID theft when I buy on next and they don't sell age related goods?