Preheat the oven to 160C/325F/Gas 2.
For the lamb tagine, heat a large ovenproof casserole or heavy saucepan on a medium to high heat.
Add the olive oil, garlic, onions, ginger and spices and season with sea salt and freshly ground black pepper. Stir, then cook, covered, on a low heat for about ten minutes, until the onions are soft.
Add the lamb, tomato purée, chopped tomatoes and honey into the saucepan, stir throughly.
Bring to the simmer and place in the oven for 1½ hours, until the lamb is tender.
Remove the lid of the saucepan halfway through the cooking time to let the liquid reduce and thicken.
If the sauce is still a bit thin, put the saucepan on the hob on a medium heat and without the lid. Stir occasionally and let the liquid reduce until a thick sauce begins to appear.
Meanwhile, for the couscous, cut the pomegranates in half and scoop out the seeds using a teaspoon and remove the white membrane around the seeds.
Place the couscous in a bowl and mix in the olive oil and lemon juice.
Pour the boiling stock or water onto the couscous and season with sea salt and freshly ground black pepper.
Allow the couscous to sit in a warm place for 5-10 minutes until the liquid has been absorbed.
Stir the chopped herbs and pomegranate seeds into the couscous.
To serve, place the tagine on serving plates with couscous and a wedge of lime. Serve alongside a bowl of thick Greek yoghurt.