A Lotus for Miss Quon - Lang Jeffries (1967) - Lai Yue Hing Tong, Fanling

So, we already know where Mark Jason's large villa is located within On Lok Tsuen. The building that stood in for the police station was the nearby Lai Yue Hing Tong (aka Fanling Babies Home). This place was originally discovered (from a film locations point of view) by Andi on his Movie Tours blog. You can see his post here. In terms of my own blog, I've only seen it the once before.