For anybody who has a similar problem – it was some code in my function.php that triggered it. It was attempting to use wp_title to call to a plugin I had deactivated/deleted.
Now resolved.
FYI, I have updated to the latest version disabled all plugins etc. It’s definitely a theme issue, but I have no idea what other code could be in the theme to cause a conflict with such a basic tag?
Any help, or ideas of where to look, would be appreciated.
