If the High Court is satisfied, on an application by the Minister, that the hearing of an appeal of a relevant vendor measure, or a variation in such measure, is likely to result in the disclosure of relevant material and that such disclosure would create a risk to the security of the State it shall exclude from the hearing of the appeal all persons except -

(a) a judge hearing the matter,

(b) a judicial assistant, or other court personnel, whose presence is necessary for the judge to hear the matter,

(c) the parties to the proceedings,

(d) the legal representatives of the parties to the proceedings, and

(e) a witness whose evidence is relevant to the proceedings, for as long as the witness's presence is required for the purpose of providing such evidence, unless it is satisfied that the interests of justice require any other person not to be so excluded.