The Magic Crystal - Andy Lau (1986) - 13 Wiltshire Road, Kowloon Tsai

I can't vouch for the interior or backyard scenes, although I'm fairly confident it is the same place, but the exterior street shots for Andy's house were done at 13 Wiltshire Road in Kowloon Tsai. In this case the plot markers at the front wall were very helpful - NKIL 4106 and 4107 are just about visible between the two doors in the screencaps. Sadly, like many older houses (many dating from the early 1950s) in this estate, this one was redeveloped along with its neighbour (#11) into the aesthetically underwhelming but expensive "Wiltshire Place" - a cluster of 4 townhouses - circa 1998. I've included a couple of images of the backyard, just in case it is indeed the same place. Sadly I don't have a historical image of the property, but Gwulo does have an image of the street from 1967 courtesy of Mike Cussans.

Cynthia is running towards Oxford Road. The wall in the background hasn't changed.