Remove the tough outer membrane from the shoulder. Coat the venison with buttermilk and marinate for 1-2 days in the fridge. Dry the meat with paper towel and discard the buttermilk. Brown the lamb knuckles in oil in a large, heavy based saucepan. Remove with a slotted spoon, season with Garlic & Herb Seasoning and set aside. Brown the venison in the same pot, then remove, set aside and Season. Add the rest of the ingredients to the saucepan and bring to the boil. Add the browned meat, cover with a tight-fitting lid and simmer gently until the meat is tender and begins to pull away from the bone (3-4 hours), or cover with foil or greaseproof paper and bake one shelf below the middle in a slow oven, 160°C, also for 3½-4 hours. Cool, flake meat, remove bones and reserve gravy.
To make the sauce, sauté the onions pre-seasoned with Green Onion Seasoning in fresh oil until soft and golden. Add the wine and vinegar and boil rapidly over a very high heat until only about ½ cup (125 ml) of liquid remains. Add the reserved pan juices and Pepper Sauce. If there is less than 2½ - 3 cups (625ml - 750 ml) of sauce, add more water. Taste and adjust the seasoning. Add the flaked meat.
Spoon the filling into a large pie dish. Wedge the onion spiked with 4 cloves or a pie funnel (as used in picture) down in the middle of the dish to support the pastry. Cover with a layer of pastry, brush with egg. (It will freeze well up to this stage). Bake at 200°C for 45 minutes. A frozen pie must be left to defrost, covered with clingfilm, to prevent moisture on the pastry. Bake for 15 minutes longer if still cold when it goes into the oven.
Brush the inside edge of the pie dish with egg to 'glue' the pastry to the dish. It helps prevent shrinkage.