This map can be viewed as an overlay to Gwulo's maps:
The map was included as part of "Mr Chadwick's Report on the Sanitary Condition of Hong Kong; with Appendices and Plans", published in November 1882.
The UK National Archives have an original, physical copy, their ref: CO 882/4/15. I photographed the map from that copy, then merged and georeferenced the digital images to create the overlay.
A copy of the report is also available to read online in the Internet Archive.