To set the correct timezone in the script add this line after ORDER BY...

date_default_timezone_set('Europe/London');

I've done some research and to prevent unapproved posts appearing in your list add the following:

t.topic_approved = 1 AND

Hi there, Great script! However I see one problem for anyone that moderates comments before they are put live. The unapproved comments show up on the pages running this script. Is there a way to ensure they cannot be seen until approved? Thanks.