I have updated my Wordpress Address (URL) and Site Address (URL) to be https:// in the General Settings of Wordpress as I have added a secruity certificate to the hosting.
Should the css url automatically update to reflect the new address if I'm using
<link rel="stylesheet" type="text/css" href="<?php bloginfo('stylesheet_url'); ?>" />
in the header code.
The url is now https:// but the css url is still pointint to http://