To strengthen and promote the principle of open justice, there is a presumption in favour of hearing a proceeding in open court to which a court or tribunal must have regard in determining whether to make any order, including an order under this Part—
(a) that the whole or any part of a proceeding be heard in closed court or closed tribunal; or
(b) that only specified persons or classes of persons may be present during the whole or any part of a proceeding.