Quote Originally Posted by webchills View Post
Instead of adding a new notifier (NOTIFY_HEADER_START) in includes/templates/YOUR_TEMPLATE/common/tpl_header.php you could also use the existing notifier NOTIFY_HTML_HEAD_START in includes/templates/YOUR_TEMPLATE/common/html_header.php and change in the observer class from NOTIFY_HEADER_START to NOTIFY_HTML_HEAD_START.
This way there is no change of existing core files required when installing the plugin.
Just changed the observer as mentioned here & removed my code from index.php - it does indeed work, blocking works & it also avoids the headers already sent issue I received before. Great observation. Now I just need to solve this caching issue as I'm about to run out of API calls for another day thanks to the same IP's