Toss the beef chunks in the seasoned flour. Heat oil in a large casserole over high heat and brown the beef in batches until deeply coloured. Remove and set aside.
In the same pot, sauté the onions and carrots for 5 minutes. Add the garlic and cook 1 minute more.
Add the tomato paste and cook for 2 minutes. Pour in the ale and scrape up the browned bits from the bottom.
Return the beef to the pot. Add the stock, thyme and bay leaves. Bring to a boil, then cover and reduce to a gentle simmer for 1.5 hours until the beef is very tender and the sauce is thick. Season to taste and cool.
Preheat oven to 200°C (400°F). Spoon the filling into a deep pie dish.
Roll out the pastry to cover the dish. Place over the filling, press the edges to seal and crimp. Cut a small steam hole in the centre. Brush with egg wash.
Bake for 30–35 minutes until the pastry is golden and the filling is bubbling.