ok, I have narrowed down the issue...
Your right it does work but not in one case, here are my test cases:
LDAP: dc=adamjseed,dc=co,dc=uk
Admin User: cn=admin,dc=adamjseed,dc=co,dc=uk
I have two users:
cn=adamjseed,ou=users,dc=adamjseed,dc=co,dc=uk
cn=guest,ou=users,dc=adamjseed,dc=co,dc=uk
what's important is that the uid=cn in both cases
guest works where adamjseed doesnt, if I change the uid (not cn) of adamjseed to adamjseed1 it then does work.
im guessing its conflicting with the dn?