Lamb: Pre-heat the oven to 425 degrees F (220 degrees C).
Bash up the coriander and mint and mix with the yogurt, garlic, and seasoning. Reserve half to use as a sauce once the lamb is cooked.
Score the lamb pieces, season with the salt and pepper and mix with half the marinade and the chickpeas, so it is all coated.
Transfer the marinade and lamb to a plastic bag and seal. Place in the refrigerator until required.
To cook, place the meat directly on the oven shelf above the tray of vegetables for approximately 45 minutes.
Vegetables: Pre-heat the oven to 425 degrees F (220 degrees C). Place all the vegetables in a roasting tray, add the chickpeas, cumin, coriander seeds, nutmeg, sea salt, pepper, and olive oil and toss together.
Cook in the preheated oven for 20 minutes then remove the foil and continue roasting for 20 to 30 minutes until the vegetables are tender and golden.