In a large bowl, toss the steak in the flour. Heat the oil in a large pan, then add the steak and cook, in batches, until golden all over. Remove with a slotted spoon and set aside.
Add the onion, carrots and 200ml stout and stir, scraping off any bits stuck to the bottom of the pan. Cook for 10 minutes, until the onion and carrot is starting to soften. Add the mushrooms and garlic, and cook for a further 2 minutes.
Return the meat to the pan, along with any juices, and add the stock, thyme, bay leaf and remaining 300ml stout. Bring to the boil, then cover with a lid and simmer for 2 hours over a low heat. At the end of cooking, stir in the redcurrant jelly, remove the bay leaf and divide the mixture between 4 x 250ml pie dishes.
Preheat the oven to 200°C, fan 180°C, gas 6. Cut out 4 lids from the pastry, large enough to fit over the pie dishes. Brush the edges of the dishes with some of the egg, then place the lids on top, pressing down with a fork to secure. Decorate with leaves made from pastry trimmings. Brush with egg and bake for 20–30 minutes, until golden.