Place the lamb and flour in a large bowl and toss to combine. Season.
Heat the oil in a large heavy-based saucepan over medium-high heat. Add the lamb and cook, turning, for 5 mins or until lamb is brown all over. Transfer to a heatproof plate.
Add the onion, fennel and garlic to the pan and cook, stirring, for 5 mins or until onion softens. Return the lamb to the pan and pour over the stout. Bring to the boil. Cook for 2 mins or until the stout reduces slightly. Add the stock, diced tomato, tomato paste and rosemary. Bring to the boil. Reduce heat to low. Cover and cook, turning occasionally, for 2 hours or until the lamb is falling off the bone.
Add the pumpkin to the pan and cook, uncovered, stirring occasionally, for 15 mins or until the pumpkin is tender and the sauce thickens slightly.
Transfer the lamb to a heatproof bowl. Set aside to cool slightly. Use 2 forks to coarsely shred the meat. Discard the bones. Return the meat to the pan and stir to combine. Season. Set aside to cool slightly.
Preheat oven to 200°C. Divide the lamb mixture among six 1½-cup (375ml) ovenproof dishes.
Place 1 pastry sheet on a clean work surface. Lightly brush with egg. Top with another pastry sheet. Use a 12cm pastry cutter to cut 4 discs from pastry stack. Cut the remaining pastry sheet in half. Lightly brush 1 pastry half with egg. Top with remaining pastry half and use the pastry cutter to cut 2 discs from pastry stack. Place the pastry discs over the lamb mixture in the dishes. Brush with egg. Sprinkle with fennel seeds and salt.
Bake for 20-25 mins or until the pastry is puffed and golden.