The CEDD's "When Hillsides Collapse" has a couple of photos of this landslide. They show a section of Peak Road just below / east of the junction with Guildford and Barker Roads had fallen away. The caption reads:
A section of the Peak Road near Magazine Gap collapsed during the rainstorm on 12 June 1966. As the road was the only route between the Peak and the rest of Hong Kong Island, residents of the Peak were temporarily isolated.
1966 landslide
I understand part of Stubbs Rd was also affected by a landslide in 1966. I wonder if it was the same date (I'll check when I get back to HK). I know the Stubbs Rd landslide destroyed the tennis court in the front garden of King Yin Lei.
View of the repair works after the landslide
1966 Stubbs Road Landslide
Hi Philk - appearing on ebay as seen here and here
Stubbs Road Landslide
Here's a photo