Finely slice and arrange the lemon in a double layer down the middle of a roasting tin. Sit the chicken on top, making sure all the lemon is covered. Season the chicken skin and drizzle with olive oil.
Roast in the oven for 15 minutes, then lower the temperature to 180ºC/350ºF/gas 4 and continue cooking for 50 minutes, or until the chicken’s juices run clear when the thickest part of the thigh is pierced with a skewer.
Leave to rest for 10 to 15 minutes.
Shred the meat from the chicken and, in a large bowl, toss with the lemon slices, lentils and leaves.
Chop the capers and mix with the lemon juice, 3 tablespoons of extra virgin olive oil and the yoghurt, then drizzle over the salad and serve.