The more I looked into this the more it looked like it could be a problem using
mysql_insert_id()
From what I can gather (please correct if wrong) mysql_insert_id() will return the insert id (of the previous successful - ie LAST BUT ONE) insert, even IF the LAST insert failed - if the connection is persistant.
Not too hot on this function so decided another route.
ie. to set the post trigger if my MYSQL Database Insert function didnt die, otherwise post trigger was constantly 'unset' every time the page ran - that seemed to do the trick.