The following persons may apply to the Crown Court to vary or discharge an order made under any of sections 48 to 51 —
the receiver;
the person who applied for the order ...;
any person affected by the order.
On an application under this section the court—
may discharge the order;
may vary the order.
But in the case of an order under section 48 or 49—
if the condition in section 40 which was satisfied was that proceedings were started or an application was made, the court must discharge the order on the conclusion of the proceedings or of the application (as the case may be);
if the condition which was satisfied was that an investigation was started or an application was to be made, the court must discharge the order if within a reasonable time proceedings for the offence are not started or the application is not made (as the case may be).