Nothing in a statutory provision (whenever made) with respect to a harbour authority shall extend to regulate or subject to control mail-bags—
(a)carried by a universal service provider in connection with the provision of a universal postal service,
(b)consigned by such a provider in the provision of such a service to another for carriage (whether to a foreign postal administration or not),
(c)consigned by a foreign postal administration to such a provider in connection with the provision of such a service for carriage, or
(d)consigned by one foreign postal administration to another and which, when in the United Kingdom, are in the charge of a universal service provider in connection with the provision of a universal postal service.