To make the labneh, mix the yoghurt, lime and coriander together in a bowl. Line another small bowl with a square of muslin. Spoon the yogurt mixture into the bowl, pull up the ends of the muslin and tie the yoghurt into a ball. Tie the ends of the muslin onto a wooden spoon and suspend over a bowl or jug. Place in the fridge overnight to strain.
Heat oven to 200C/180C fan/gas 6. Toss the carrots with 1 tsp of the oil, 2 tsp of the lime juice, the cumin and lots of ground black pepper. Tip onto a foil-lined baking tray and roast for 20 mins. Turn the carrots and return to the oven for a further 10 mins or until tender and lightly browned. Set aside.
Cut the avocado in half and remove the stone. Scoop out the flesh from each half in one piece with a serving spoon. Slice on a chopping board, then toss with the remaining lime juice.
Untie the labneh and spread it over two plates, top with the salad leaves, carrots and avocado. Drizzle over the remaining oil, sprinkle with the seeds and serve with lime wedges.