2 Aug 25, 2010 03:13
Each blog and user have their own locale, so you probably have to go to each and set them all to en-GB. Then each post already made has a locale all it's own so you probably have to edit each post to make them all be en-GB. Then you may as well go to Global settings and disable or delete the en-US locale. I'm pretty sure that'll get everything now and forever being "old school English".
If ya got a lot of posts it's probably easier to do it in phpmyadmin. Depends though.