Nope that didn't work Huw, just returned an error...
UPDATE FORUM_FORUM_TOPICS SET FORUM_ID = 10 WHERE FORUM_ID = 57
-2147217865 | [MySQL][ODBC 5.1 Driver][mysqld-5.1.73-log]Table 'db_name.forum_forum_topics' doesn't exist
UPDATE FORUM_FORUM_TOPICS SET FORUM_ID = 10 WHERE FORUM_ID = 5