Just went to Amazon.co.uk and got the pop-up.
clicked on them more info box and it sent me to the following URL
https://www.amazon.co.uk/exec/obidos/flex-sign-in/ref=nvr_pop_r/026-3452648-4753217?opt=a&page=new-visitor-reward/nvr-register.html&response=new-visitor-reward&tag=myrev09-21
Hope this helps