Bring the stock to the boil along with all the other ingredients up to and including the star anise.
Add the chicken breasts, cover and simmer for approx. 10 mins., add the rice and spring onions to the soup, cover and simmer for approx. 20 mins., stirring occasionally. Remove the chicken, pull apart using two forks, return to the soup with the spring onion greens, courgette, lime zest and juice, heat gently. Scatter the coriander over the top.