Put stock in a saucepan and bring to the boil. Add lime leaves,
galangal, lemongrass, sugar and fish sauce, and simmer for 2 mins.
Add thinly sliced chicken, coconut milk and lemon juice, bring
to the boil and simmer for a further 2 minutes.
Add lime juice and bruised chillies, and bring back to boil, then
take off heat.
Serve garnished with coriander.