Domestic helpers in Southern district are paid about 13 per cent more than those whose employers live in Wong Tai Sin, according to the latest survey of maid salaries across Hong Kong.The wage findings, released on Wednesday, showed a higher demand for domestic helpers in Wan Chai and Sai Kung, where average salaries were up by 9.6 per cent and 7.1 per cent respectively from a year ago.The annual survey, conducted by HelperChoice – an online platform that matches families with domestic helpers …