Just for the record, Up until 2017 the Duchy oyster beds were in fact being farmed by a private company, and simply leasing the facilities from the Duchy estate – so not wage slaves.
If filmed after 2017 they are not harvesting. The Duchy is doing conservation work on the beds to re-establish native oyster species. No doubt when they are developed enough for harvesting the beds will again be worked by a private enterprise.