procedure under Ord 53 provided important safeguards for public body.
would normally be abuse of process to seek declaration or injunction outside
applicant for JR seeks to protect rights or interests protected only in public law,
must use Ord 53.
as ‘procedural exclusivity principle’]
Certain types of collateral attack.
Where none of parties objected to remedy being sought outside Ord 53.
other exceptions might exist left to be determined on case-by-case basis.