4. The originating summons shall be headed with a reference to the Trade Unions Law, Cap. 172, and also with a reference to the decision of the Registrar of Trade Unions which is appealed against, and shall contain or have scheduled or annexed thereto a concise statement of the grounds of the appeal, and no grounds other than those comprised in such statement shall (except with the leave of the Court and on such terms, if any, as the Court shall think just) be allowed to be taken by the appellant at the hearing of the summons.