Parkeston Quay is known as Harwich International Port nowadays, Stena do still operate the ferry to the Hook but only traditional type RoRo(albeit new)not the HSS anymore. Other stuff operates out of there too but not 100% on details these days.
The old quay actually in Harwich still operates too, Jags n Land Rovers, JCB n similar was going from there but not looked properly for a while.