The final location from this brief delve into 1970s erotic cinema is a location on Barker Road, just around the corner from the Chief Secretary's residence. Although it is still marked as "Headquarters House" on some maps, this residence underwent a name change following the handover and is officially known as the "Commanders Residence". Before the handover it was occupied by the Commander of British Forces so it makes sense that it is now occupied by the Commander of the PLA's Hong Kong garrison.
This film appears to have captured the site before the house was built. This ties in with the information on Wikipedia that states the house was in use from 1978 onwards. Aerial images show an empty plot as late as June 1977. The podium terrace that the actors are standing on in the scene below was most likely already there for the previous occupant - a building called "Dunedin". If you look at image 3 below, you can see the edge of an empty patch on the left side of the frame, so it's possible the site had been recently cleared in order to make way for the building of the new house.
Prior to living here at 11 Barker Road, the official residence of the British Commander was Flagstaff House - coincidentally used in another mid-70s film of the same genre Emmanuelle 2 (the former resident of Flagstaff House at that time was kind enough to let me know that the interiors seen in that film were indeed the real interior of Flagstaff House at the time).
The property's driveway was also used as the driveway to the house owned by Angelo and Linda, Annie's obsessive friends, although the house in the film was definitely not one in Hong Kong. At the end of this scene, the friends are filmed coming down the driveway in their Rolls Royce as they chase her to the airport. Some geographical movie jiggery-pokery ensues as the Land Rover containing Annie emerges from the opposite driveway - the entrance to Bracken Hill (#12 Barker Road) - which is lower down the hillside from where she was supposedly picked up.
