So far as I understand it, the process runs as follows:
1. Buy/apply SSL for the domain
2. Add the following line inside the PHP brackets in config.php:
$_SERVER['HTTPS'] = 'on';
Is that everything, or have I missed a step? Would just like to clarify this is the way to do it before proceeding, as there doesn't appear to be a tutorial on it - but hopefully this thread can help provide the basics in a single place.