Can anyone help me with reinstating a DF4WP connection please.

In Dataflex 2016 18.2 we had a Wordpress site accessing another server running a Dataflex webapp. The customer upgraded their site and I am having trouble getting the plugin working with the new site. The documentation 'TheDF4WPPlugin.pdf' mentions a 32 character "Secret" which is needed to set the psWPSecret property in the web application. I can't find any reference to this property in the web app that was working with the old site. Is this psWPSecret just a generic name? The closest I can find is psWPEncryptSecret in cWPWebApp.pkg but I can't see where this value is actually set.

Any advice would be appreciated thanks. Paul