Notwithstanding anything herein contained, where any application is made or document tendered for record or registration by any person purporting to act as a legal practitioner on behalf of a client, the Registrar shall not entertain the application or accept the document unless that person is an advocate duly enrolled in the High Court and the holder of an unexpired certificate entitling him or her to practise in the courts of Uganda; but where the application is entertained or document accepted by the Registrar in error, nothing in this section shall invalidate or nullify the effect of any action of the Registrar taken upon that application or acceptance.