New Territories self-built house

Buying an old property under your own name for redevelopment. Current deed available. Bank offers 70% mortgage. Transaction handled by a law firm. Options: ground floor, mid-floor, and 2nd floor with rooftop. Prices are 3.2 million for ground floor, 3.2 million for mid-floor, and 4.5 million for the 2nd floor with rooftop (sea view).