Season the pork well, with salt and pepper. Heat 1 tablespoon of the oil in a large flameproof casserole and fry the pork in batches until browned on all sides, lifting out with a slotted spoon on to a plate. Add the remaining oil to the casserole and gently fry the onion and leeks for 5 minutes.
Return the pork to the casserole, add the bay leaves and stock and bring to a simmer. Stir in the pearl barley. Cover, reduce the heat to its lowest setting and cook for about 1½ hours until the pork and barley are tender and the cooking juices have thickened.
Mix together the flour, suet and a little salt and pepper in a bowl. Add the measurement water and mix with a round-bladed knife to a soft dough, adding a dash more water if the mixture feels dry and crumbly, but don't make it too sticky.
Stir the prunes into the stew and season to taste with salt and pepper. Using a dessertspoon, place spoonfuls of the dumpling mixture on the surface of the stew, spacing them slightly apart. Re-cover and cook gently for a further 15–20 minutes until the dumplings have risen and have a fluffy texture. Serve in shallow bowls.