If a child who is before a Childrens Court judge—
(a) is not represented by a lawyer; or
(b) if represented by a lawyer, has not elected, or withdraws an election, to be tried without a jury under another provision of this division; or
(c) if the judge decides that in the particular circumstances it is more appropriate for the child to be tried by the judge sitting with a jury;the child must be tried before the judge sitting with a jury.