To prepare the potatoes, slice the new potatoes in half lengthwise. This makes them thinner than if you cut them width wise and they will cook faster. Drizzle with olive oil and salt and pepper. Scatter with some thyme sprigs and place in the oven for about 10 minutes.
When your ten minutes is up, add the chicken to the pan and place the lemon slices on top. Put the tray back in the oven for another 20 minutes.