Heat olive oil in a heavy-based pan and fry pancetta until crisp at the edges.
Stir in onion and garlic and fry for 3 minutes until translucent.
Add paprika, mustard, treacle, Worcestershire sauce, tomatoes, sugar, tomato purée, and haricot beans.
Boil for 10 minutes until the liquid reduces to a thick consistency and season well.
Remove sausage skins and roll meat into golf ball sized meatballs.
Heat olive oil and fry meatballs for 10 minutes until golden-brown and cooked through.
Boil peeled potatoes for 5 minutes until tender, then drain.
Grate the cooled potatoes and mix with spring onions, flour, half the butter, and seasoning.
Shape the mixture into four flat rounds.
Fry potato cakes in oil and remaining butter for 3 minutes per side until golden.
Serve beans over potato cakes and meatballs garnished with parsley.