The cranes in question and all the others with the exception of one at City Terminal and one at Mayflower, there is not one at all at Ocean, were no longer used by the shipping companies i:e Cunard/ P & O/ Princess, RCCL as there is no need for the use of the cranes on modern cruise ships as most of the stores etc is transferred to the ship through the side of the ship using forklift trucks and tele-handlers, this way saves the companies the extra expense of the use of the cranes when in port. The older ships still in use i;e Saga Ruby & Sapphire still need the cranes when they call in as all the luggage etc.. is lifted off the ships open aft decks via the use of the crane. If for instance a "SAGA" goes to QE11 terminal (Very rarely) a portable crane is brought in.
Not good for the old cranes, I don`t know whatever became of them, probably scrap but it all saves money.
Another fore instance on the shipping companies saving (Port Expenses) if you go back and look at the QM2 re-fit videos (Nov 2011) a skytrack is mentioned, this was added to QM2 so as they could wash all her outer windows when in port without having to employ the use of a "Cherry Picker" Thus saving added expense