Thought I'd rejuvenate this post as the offer has changed. You no longer need to register and activate your account, which is a plus. So use any email address, but obviously a real delivery address.
Simply fill in your details to receive 2 bars and this quickstart guide.
As per the comment from mastablasta, there's no need to enter DOB & height. But if you must, note there's an error with the DOB field. You need to enter DD MM YYYY.