20.—(1) Where a Commissioner considers that an application, appeal or reference made to him gives insufficient particulars to enable the question at issue to be determined, he may direct the party making the application, appeal or reference, or any respondent, to furnish any further particulars as may reasonably be required.
(2) In the case of an application for leave to appeal, or an appeal from an appeal tribunal, a Commissioner may, before determining the application or appeal, direct the tribunal to submit a statement of such facts or other matters as he considers necessary for the proper determination of that application or appeal.
(3) At any stage of the proceedings, a Commissioner may, on or without an application, give any directions as he may consider necessary or desirable for the efficient despatch of the proceedings.
(4) Without prejudice to regulations 18 and 19, or to paragraph (3), a Commissioner may direct any party before him to make any written observations as may seem to him necessary to enable the question at issue to be determined.
(5) An application under paragraph (3) shall be made in writing to a Commissioner and shall set out the direction which the applicant seeks.
(6) Unless a Commissioner shall otherwise determine, the office shall send a copy of an application under paragraph (3) to every other party.