Statutory harbour authorities are public authorities for EIR purposes. See FER0195081, FS50378095, and EA/2006/0083. Some of them are also covered by FOIA by virtue of their power of nominating special constables.
There is an argument that all trust ports ought to be subject to FOI as they are publicly owned.
Even privately owned ports have important public functions.
see: Trust ports
Whatdotheyknow.com tag: port_authority