Boil the potatoes for 10 mins, then drain well and cut in half. Heat 2 tablespoons of the oil in a large heavy pan. Fry the potatoes until golden and then transfer to a plate.
Season both sides of the liver slices with the salt, some pepper and the paprika. Melt the butter in the frying pan until it is hot, then brown the liver on both sides. Move the liver to a plate and keep warm.
Add the remaining oil to the pan and fry the bacon, onion and garlic in it, stirring all the time until golden brown. Mix in the apple and cook for a further two minutes Then add the tomatoes, thyme and the worcertershire sauce. Bring to the boil, reduce the heat and simmer for 3 minutes.
Stir the potatoes into the sauce and arrange the liver slices on the top. Cover and heat throught for 3 or so minutes more. Season with a bit more pepper, sprinkle the parsley over the top and serve. Great with home baked brown bread!