Preheat the oven to 200°C.
Boil the potatoes in salted water for 15-20 minutes until nearly cooked through.
Fry the onion, garlic, carrots, and celery in half the olive oil until softened.
Add tomatoes, sauces, spices, herbs, wine, stock, and vinegar to the vegetables and simmer for 5 minutes.
Fry the beef mince in the remaining oil until golden brown and stir into the vegetable sauce.
Add frozen peas to the potatoes and cook for a few minutes until tender.
Fry spring onions in butter, then stir in milk and heat through.
Drain potatoes and peas, then mash with the warm milk mixture until combined but chunky.
Spoon beef into a pie dish, top with champ, cheese, and paprika.
Bake for 25-30 minutes until the topping is golden-brown.