Twenty years ago, Louis Mullan was a 15-year old boy, on holiday for Christmas in Takua Pa, near Phuket, with his parents and kid brother Theo, 11. On Boxing Day the family, from Truro, Cornwall, were planning a day of snorkelling when his father, standing on the beach, noticed something unusual out in the ocean and told his sons to come and take a look. Minutes later all four of them were swept off their feet by the surging tsunami wave, caused by an earthquake measuring 9.1 on the Richter