Hi RichardNZ - Just tried your link to the advanced search form with the latest versions of Google Chrome, Mozilla Firefox and Microsoft Edge browser and all are working fine.
Suggest uninstalling your version of Chrome browser and reinstalling Version 63.0.3239.84 (Official Build) (64-bit) again.
Just wondering if it's actually trying to get you to log-in to Chrome instead - or perhaps to your Google account?
It is not the forums.auran.com page requesting such image verification.
Edit Update: Just another thought: Have you tried initiating your search from the underscored text string below the magnifying glass at the top right? The one that is titled "Advanced search"?
The magnifying glass icon is typically used after you have entered a text string into the entry box to the left.
Either way, however, it is not normal to be prompted for a 'veri-sign' authentication on this particular search form.