Live Action Reference Photo A-SPEC-87 - Alice and Sister Walking Home
This is pretty obscure, and who knew the lengths they went to to stage these live action reference shots.
Can't believe they actually built a bridge for them to walk across.
I've added a detailed close up of Kathy and the actor portraying the sister. Unfortunately you cannot see the actor's face, so you can't tell if it is Heather Angel or not. According to IMDb she would have been 41 at the time of this shot. I can only find photos of her from the 1930s to compare, so it is very hard to say.