Whoisit – so as not to confuse you and to allow posters to provide considered replies, could you please advise:
1) The year in which your building was constructed;
2) Whether your bathroom is original (i.e. un-renovated since the completion of the building);
3) Whether the wall adjoining the bathtub is internal to your Unit or on a perimeter wall;
4) If the leakage into the Unit below continues.