52.—(1) Where an agent has been authorised under section 82, the registrar may in any particular case require the personal signature or presence of the agent or the person authorising him to act as agent.
(2) Where after a person has become a party to proceedings before the registrar, he appoints an agent for the first time or appoints one agent in substitution for another, the newly appointed agent shall file Form TM33, and any act required or authorised by the Act in connection with the registration of a trade mark or any procedure relating to a trade mark may not be done by or to the newly appointed agent until on or after the date on which he files that form.
(3) The registrar may by notice in writing sent to an agent require him to produce evidence of his authority.