(2)  At any stage of the proceedings under this Rule the Court may, on the application of the plaintiff, and on such terms, if any, as it thinks fit, appoint any one or more of the defendants or other persons as representing whom the defendants are sued to represent all, or all except one or more, of those persons in the proceedings; and where, in exercise of the power conferred by this paragraph, the Court appoints a person not named as a defendant, it shall make an order under Rule 6 adding that person as a defendant.

(3)  A judgment or order given in proceedings under this Rule shall be binding on all the persons as representing whom the plaintiffs sue or, as the case may be, the defendants are sued, but shall not be enforced against any person not a party to the proceedings except with the leave of the Court.

(4)  An application for the grant of leave under paragraph (3) must be made by summons which must be served personally on the person against whom it is sought to enforce the judgment or order.

(5)  Notwithstanding that a judgment or order to which any such application relates is binding on the person against whom the application is made, that person may dispute liability to have the judgment or order enforced against him on the ground that by reason of facts and matters particular to his case he is entitled to be exempted from such liability.

(6)  The Court hearing an application for the grant of leave under paragraph (3) may order the question whether the judgment or order is enforceable against the person against whom the application is made to be tried and determined in any manner in which any issue or question in an action may be tried and determined.