Grease the cake tin with lard.
Place the bones, vegetables, bouquet garni and peppercorns and cover with a litre of water.
Bring to the boil and simmer for at least 1 and a half hours.
To make the pie filling, place all of the ingredients into a large bowl and mix well with your hands. Season with salt and freshly ground black pepper.
Cover the meat and place in the fridge until needed.
Preheat oven to 180C/350F/gas 4.
To make the pastry place the lard, butter and water in the small saucepan and heat until the lard and butter have melted.
Sift the flour into the mixing bowl and season with salt and freshly ground black pepper and mix well.
Make a well in the flour and pour in the hot lard/butter mixture.
Use a wooden spoon to mix in and then use your hands to bring to a dough.
Transfer the dough to a lightly floured work surface and knead until you have a very smooth dough. Wrap in clingfilm and place in the fridge for half an hour.
Remove from the fridge and take 2/3 of the dough and roll out on the lightly floured work surface to fit the cake tin with at least a 1cm over-hang. Wrap the remaining pastry for the lid in clingfilm and set aside.
Line the cake tin with the pastry.
Fill the pie with the pork mixture.
Roll out the remaining pastry to make the pie lid and place on top of the filled pie base. Press down the edges with the palm of your hand and trim.
Use your fingers or the handle of a wooden spoon to crimp round the edges.
Make a hole in the centre of the pastry lid. Make a funnel with a folded piece of kitchen foil and place in the hole ensuring the walls of the funnel are flush to the pastry.
Knead any excess pastry to a smooth ball and roll out. Cut out decorations such as leaves and use beaten egg to stick to the top of the pie.
Place the pie in the fridge for an hour.
Remove from the fridge and glaze the pastry with the beaten egg.
Place in the oven and bake for 1 and a half to 2 hours or until the temperature of the meat comes to 74C/165F using a meat thermometer. If the pie starts to darken in colour too much during the cooking time place a sheet of kitchen foil over the top for the remaining cooking time.
Remove from the oven and allow to cool to room temperature.
Soak the gelatine leaves in cold water for 20 minutes.
Strain 500ml of pork stock into a clean saucepan and heat up to boiling. Take off the heat.
Remove the gelatine leaves from the water and add to the hot stock. Stir until dissolved. Allow the stock to come to room temperature.
When both the pie and the stock have cooled to room temperature pour the stock into the pie via the central hole.
Chill the pie in the fridge until the jelly is set – about 2 hours.
Take out of the fridge, remove the cake tin and serve.
