I got a plumber up to see, he suggested fitting external pipe to the master bathroom shower and sink but i do not think he is sure where the leak comes from. The leak comes from the turning point of the 'L' shape wardrobe. So without removing it to inspect, a lot of guessing opinion is given by id, mgt and plumber. As the wardrobe is only a few months and cost me a few thousand dollars, I want to reuse it as much as possible but was told by ID once remove it cannot be fitted back.