hi andy,
I know your fix. if its things like calias and energy pills etc spam in the top of your header.php file. i fixed mine last week,
if you go to your directory,
wp-content\themes\twentytwelve\header.php will probably be in all your theme files , i had to clear it from 5 .. twentytwelve is example not actual, follow root to all your themes first to check.
you will see a lot of spam at the top of your header text.
message me if you want help.
