Preheat oven to 200°C fan.
Heat oil in a large pan. Cook onion, carrot, celery 10 minutes. Add garlic 1 minute.
Add beef mince. Break up. Cook 8 minutes browning.
Sprinkle in flour. Stir 1 minute. Add tomato paste, Worcestershire, wine, stock and thyme. Bring to simmer. Cook 15 minutes until thick.
Stir in peas. Salt and pepper to taste. Pour into a deep baking dish.
Boil potatoes 20 minutes until tender. Drain. Mash with butter and milk. Salt and pepper.
Spread mash over filling. Use a fork to make ridges. Sprinkle with cheese.
Bake 25-30 minutes until top is golden and edges are bubbling.