Finely chop the onion, garlic and carrots.
Heat the oil in pan and gently fry the onion until softened, then add the garlic and carrot. Put a lid on and sauté for 5 minutes over low heat.
Add the herbs and stir gently for a couple of minutes, then add the tomato purée.
Keep stirring for a minute, then add the chopped tomatoes, gravy and stock.
Bring to the boil and cook over low heat for 10 minutes, then add the chickpeas and your chosen greens and cook for another 5 minutes or so.
Add more stock if the stew is getting too thick.
Add the lamb pieces and heat through.
Serve with chopped mint leaves and crumple feta on top, if liked.