Provided always that in all cases where the entry of any transfer shall be omitted or delayed beyond the period provided for the entry thereof it shall be lawful for the Commissioners for the time being of Her Majesty’s Woods, Forests, Land Revenues, Works, and Buildings, or any two of them, for any reasonable cause to them shown for the omission or delay, to permit the making of any such entrynunc pro tunc,and the same, when made under such authority, shall be valid as if made within the aforesaid period limited.