I believe this is what Jez and Jane described.

That's impossible Jez is facing her and didn't see anyone on the street and I can't believe she wouldn't say anything when passing within a couple of feet. You must be able to hear her on quiet deserted street walking past. My first thought was she may have seen the man crossing before she got to them and turned left onto the lane.
I would say that when I spoke with Gerry it was possible to recognize someone I knew who was passing on foot at the crossing at the top of the hill or to describe approximately someone unknown from that distance.
Q. Relative to whether I know Jane Tanner;
Now I know her name, description of the clothes and photos which I have seen in the press. At that time I knew of her as a member of the group but did not know her name. I do not remember having seen her when I spoke with Gerry, but I believe I saw her when I first ventured out. She was stopped on the street in front of one of the group's apartments when I passed her down towards the exit to my apartment. I do not know if it was her apartment or not. I remember that she was wearing the colour
purple. (JW)

"He was adamant that he did not see any one else in the area. When spoken to in reference to Jane Tanner walking by, he again stated that he saw no one. He also stated that he did not see or hear anyone to his right. He was aware of the recent picture in the papers re the person with a child wrapped in a blanket and in a males arms allegedly walking across the junction to his right but again stated that he did not see any one.
The conversation with Gerry lasted for about three minutes during which Gerry was chatty and in his normal self. Jeremy then made his way back to his apartment."
http://www.mccannpjfiles.co.uk/PJ/JEREMY_BRIGET.htm