Preheat oven to 180°C.
In a large pot, add potatoes then cover in cold salted water. Bring to the boil then simmer until just past tender. Drain and pass through a potato ricer or mash with a potato masher.
In a small bowl, add hot cream and butter and mix until smooth and creamy. Season with salt and pepper. Set aside and keep warm.
In a large frying pan, heat oil over moderate heat. Add onion, celery and garlic and cook, stirring regularly, until onion is soft and translucent.
Add lamb mince to pan and cook until brown. Stir constantly to break the meat up and skim occasionally to remove fat.
Stir through carrot, tomato paste and Italian seasoning. Add wine and cook for 2 minutes. Pour in stock concentrate mixed with hot water and heat until bubbling.
Transfer to a casserole dish then spread warm mashed potato evenly over lamb mixture. Top with cheese then bake in oven for 30 minutes until golden. Serve with your favourite vegetable side.