Perfect, everything's sorted. I used that query in the Database Tools area:
UPDATE `database_name`.`ubbt_USER_GROUPS` SET `GROUP_ID` = '4' WHERE `ubbt_USER_GROUPS`.`GROUP_ID` =3
Initially I got an error, and I realized that was because I had already added all the members to the Users group. So I just created a temp group, moved members to that, and substituted the appropriate group ID numbers in the SQL statement, etc.
I didn't even need to re-assign my moderators, because they were already in the 'global moderators' group, so I just moved them from there.
Andrew
Last edited by sw55; 05/01/2013 3:39 PM. Reason: Added more info