First, I love the shots, and BW is a great choice.I'm particularly fond of number 3. There's something about that man's head turning look as he's walking.
I don't have photoshop, but this is a case were I sort of wish that the woman with the white jacket was off camera. I don't know if you can do this Colin, or if you'd even want to... I think this photograph might be even stronger without us knowing, or assuming we know, what this fellow was looking at with such seeming intensity. The question of what caught his interest and the black and white treatment, plus the architecture, the lighting and the wet stone pavement... What do you think?