Peripheral vision seems to have been discounted for some reason ... that part of vision that occurs outside the centre of gaze ( try looking intently at something a foot or two in front of you and notice how much else is in your field of view )
Are we assuming that both Gerry and Jez suffer from 'tunnel vision' ? ... because for neither of them to have noticed Jane at any point whilst she walked the length of that street, they would have to be
I agree Icabod but on this thread there is much speculation when so many factors are known within a tolerable margin of error.
Bear in mind though that the average person has a poor appreciation of the critical elements time, distance and mass.
So for the case in point:
Sunset time 20:30
Time span of dusk period 30 minutes
Weather (clear or cloudy sky) ?
Phase of moon ?
Distance from OC Reception to road junction Rua Agostinho da Silva (approx. 45m)
Road dimensions. (approx. 6m paved blacktop and 2 x 1.8 m sidewalks)
Time taken by Jane to walk approximately 45 metres on cobbles in flipflops (40 seconds)
The time at which Jane took her walk 21:10?
Number and positions of lighting columns 3 on east side of street between OC Reception and Rua Agostinho da Silva
Centre distances of lighting columns approx. 28m
Height of lighting columns approx. 3- 4m
Predominant background colour. White
Position of protagonists. ?
Human field of vision.(120degrees binocular and approx. 160degrees all round)
The human eye is attuned to picking up movement.
Weight of average 3-4 year old (actually about the same as normal duty car battery).
If Gerry stood where he said he stood then Jane was in his field of vision for 20 seconds or so light source to her right silhouetted on white back ground to her left.
I'll leave others to join up the dots.