Pour the oil into a large ovenproof pan, add the potatoes, shallots, garlic, oregano, bay leaves, salt and pepper.
Cut the lamb into 8-10 large chunks. Place in a bowl, squeeze over the lemon juice and season, to taste, with salt and freshly ground black pepper.
Arrange the lamb and squeezed lemon quarters on top of the vegetables and pour over the stock. Cover with a tight-fitting lid and cook in the oven for 3½-4 hours, or until tender, basting the lamb with the juices occasionally.
For the salad, add the beans to a pan of boiling water set over a medium heat and simmer for a few minutes. Prepare a bowl of ice water. Once tender, drain the beans well and place in the ice water. Drain again once cold.
Combine all the other salad ingredients together in a bowl and season well.
To serve, spoon the lamb onto a large warm platter and top with the potatoes, shallots, garlic and herbs and spoon over the juices. Serve with the salad.