I have found a colonial film archive with a database of over 6,000 colonial films. Here's the link - http://www.colonialfilm.org.uk/
There's an extensive list of films on Hong Kong for example this film from 1958 - http://www.colonialfilm.org.uk/node/4438
Here's the list of films
Here's the list of films showing Hong Kong:
http://www.colonialfilm.org.uk/country/hong-kong?sort=year&rpp=48