519.This section prohibits a service court from passing a sentence of imprisonment, a sentence of detention under section 209 or 218, a detention and training order or a sentence of service detention on an offender who is not legally represented. But this does not apply if the offender refused or failed to apply for representation after being informed of his right to apply for it, or was aged 21 or more when convicted and has previously been sentenced to imprisonment (not counting a suspended sentence which has not been activated). The section reflects section 83 of the Sentencing Act.