“37. In my judgment the power conferred by paragraph (1) of rule 52.9 is emphatically not a power to, in effect, entertain an appeal against the grant of permission … In my judgment the power to set aside a grant of permission to appeal is not available for the purpose of second-guessing the single judge who granted the permission and thereby generating satellite litigation; rather, its purpose is to enable the court to do justice in those rare cases where something in the nature of an irregularity has occurred in the granting of permission, whether by reason of the single judge having been misled or for some other like reason. 38. … 39. I would accordingly dismiss this application, and in doing so I would express the hope that in future practitioners will think twice before launching an application of this kind, in the knowledge that only in very limited circumstances will such an application be likely to succeed”