Heat half the oil in a large saucepan over a medium/high heat, add half the beef and cook for 4-5 minutes until browned all over. Remove with a slotted spoon and set aside. Repeat with the remaining meat.
Add the remaining oil to the pan and cook the lardons, onions and mushrooms for 3-4 minutes.
Return the meat to the pan and stir in the flour, cook for a minute then gradually stir in the stock, wine and herbs. Season, bring to the boil, reduce to a gentle simmer, put on the lid and simmer for 1 ½ hours, stirring occasionally until the meat is very tender. Stir through the redcurrant jelly, check for seasoning and allow to cool for 20-30 minutes before transferring to a 20-22cm pie dish.
Preheat the oven to 190°C, 170°C fan, gas mark 5.
Brush the edge of the pie dish with beaten egg, unroll the pastry and with a sharp knife cut strips of pastry (approx 2cm wide) from the edges and use to form a rim on the pie dish. Brush the edge with beaten egg to help the pastry stick.
Carefully lift the remaining pastry, lay over the dish and press down the edges to form a good seal.
Trim off any excess pastry with a sharp knife (reserve the trimmings to decorate) and flute the edges. Make two holes in the centre of the pie to allow the steam to escape.
Re-roll the trimmings and cut out leaves or other shapes of your choice. Brush the pastry top with egg wash, arrange leaves on top and brush again. Bake for approximately 25-30 minutes until the pastry is golden brown.