Soothing chicken and pearl barley soup

Name: Soothing chicken and pearl barley soup
Ingredients: 2 tbsp olive oil; 1kg/2lb 4oz chicken legs and thighs, skin removed; 3 large garlic cloves, finely chopped; thumb-sized piece ginger, peeled and crushed; 1 tsp cumin seeds; 2 dried bay leaves; 1 tsp ground turmeric (or 1 small piece of fresh turmeric, skinned and finely sliced); ½ tsp coarsely ground black pepper; 175g/6oz pearl barley; 1 litre/1¾ pint hot chicken stock made with stock cubes or just-boiled water; 1 lemon, juice only; large handful flat leaf parsley, finely chopped; 25g/1oz finely chopped chives; extra chilli flakes (optional); salt, to taste