Roast the game bones at 180°C/gas mark 4 until golden brown. Heat the oil in a large pan, add all of the chopped vegetables and until beginning to colour. Deglaze the pan with the sherry and Madeira, then add the roasted bones and cover with water. Add the peppercorns and bayleaves, then simmer for 3 hours. Pass through a sieve lined with muslin, repeating as necessary to remove the solids. Season to taste and reheat as necessary.
To make the dumplings, combine all of the ingredients together and roll into