No it is not necessary to register to make a purchase from the web site. The advantage of registering is that if you return to make further purchases it makes the ordering process easier and quicker for you. Your details such as billing and delivery addresses, as well as payment details, except your credit card number and security code, will already be filled in, though of course it is easy to alter these if they have changed since your previous visit. We do not hold your card number and security code or ever see them for additional security reasons.
Also if you register you will be able to track your orders and see you account history as well as benefiting from receiving special offers and keeping you informed of new products when they become available, though of course you can choose not to receive such information if you so wish.