One thing with salt is that there is lots of it in the ocean and not all that hard to make. Given the size of the island I am sure that at the very least there was a lot of brine water available. That can be used for pickling vegetables or even meat. Meat you say, well corned beef is a pickled meat. It is soaked in brine and spices. So you get the picture of what a pickled meat could be like. I am guessing that salt and brine were pretty common in Britain at that time. But I have not confirmed that at all.