In Safari, How do I remove or prevent CONFIRM I AM HUMAN window

In regard to one website, when I add the correct address to the web address bar, I get the window:

LET'S CONFIRM YOU ARE HUMAN. YOU NEED TO SOLVE A SECURITY PUZZLE BEFORE PROCEEDING TO YOUR REQUEST. etc. etc.

Apple Tech tells me it's a website concern, the address - Officeworks.com.au - Office works tells me it should go away after the puzzle has been solved. I'm jacked off with the number of times it has been solved.

Just a point of interest - Google Chrome has the same issue.

What does this mean, how can I solve it?