Place flour in a bowl and season with salt and pepper to taste.
Dredge the cubed lamb shoulder in the seasoned flour and set aside on a plate. Reserve the excess flour.
Heat half of the butter and sunflower oil in a large stew pot. Sear half of the dredged lamb. Remove from the heat and set aside, repeating with the remaining butter, oil and lamb.
Add the onion and garlic to the pan (you might need another splash of vegetable oil) and saute until browned. Scape up any bits stuck to the bottom of the pan. Add the remaining dredging flour.
Return the seared lamb to the pot along with the lamb ribs, if using, the carrots, swede, lamb stock and Worcestershire sauce.
Simmer gently for 45 minutes with the lid slightly off.
To prepare the dumplings, place the flour, salt and baking soda in a small bowl.
Rub in the butter with your fingertips until it resembles coarse breadcrumbs.
Stir in the herbs and add the milk. Mix well. The batter will be thick and wet.
Drop by the spoonful onto the top of the simmering lamb stew. Pop the lid on and cook for another 15 minutes.
Notes
To reheat leftovers, simply cover and place in the oven at 180 C/350 F for 30 minutes.