The first section of the sequence shows a long straight stone staircase leading from what looks like a Govt housing estate.
The existence of similar steps in HK is quite limited, so the location was narrowed down to a few places and the fact that a lot of filming for this movie had gone on in Aberdeen meant that the steps from Shek Pai Wan estate were the main contender. My problem, as always, is that the area has changed enough to make a 100% confirmation difficult. In the case of the Shek Pai Wan estate, the original estate was demolished and subsequently rebuilt in the late 1980's. Coupled with the amount of redevelopment around Aberdeen in general (copious additional roads, not just buildings) meant I wasn't confident enough to post. Thomas has subsequently provided some decent aerial comparisons here and here which show the staircase in the hillside and the estate buildings at the top - under construction in the colour picture and top centre left in the black and white one.
Anyway, in response to Arthur's investigation's regarding a screen grab from the next part of the sequence (see below), it has made me confident enough (99%) to say I have the right place. The sequence follows the children running down the steps and then there is an edit point where they then arrive at Cleopatra Jones and her buddy waiting for them. The edit point could've meant this second scene was filmed elsewhere but it turns out Arthur was able to identify the location as Tung Shing Street in Aberdeen - a few metres away from the bottom of the Shek Pai Wan steps.
Here are Arthur's comments:
The [second] photo shows "務實中學" [mou6 sat6 jung1 hok6] at the back...the site is currently occupied by Port Centre of 38 Chengtu Road, Aberdeen.
For the "美樂電器行" [mei5 lok6 din6 hei3 hong4 - this is the shop on the corner next to the "No Right Turn"s sign]...the same site was later occupied by Yu Lei Tai - one of the earliest "cha chan teng" in HK - ...it was at the end of Tung Shing Rd, near the petrol station.So the camera was on Tung Shing Road looking northwest and it turns out that the block of buildings on that side of the street are still around (built in 1953). The shop that was once 美樂電器行 is now a Circle-K.
Anyway, a big thanks to Arthur and Thomas once again for some great location spotting.