Looked through hundreds of Flickr photos over the last few days, here are the few of possible interest I have found.
Taken 14th September 2007 at 8pm, this one is from far away but looks very similar to me - Zoom in at the extreme left to the two figures behind the black lampost, and look at the rear figure.
Taken 14th September 2007 at 5pm, much lower quality - Look at the person walking to the far left of the photo, left of the silver taxi. IMO this is less likely as they appear older and more built.
Taken 14th September 2007 at 11pm which is clearly incorrect, although could still be the correct date - Look at the extreme left again, person sitting down just to the right of the woman standing in blue jeans.
4, 5 and 6.
Have listed these seperately as I don't have much faith in them, but will attach just in case.
4 - Person walking with their back to camera, could be a 'match' with a haircut and tucked shirt in, but feels unlikely even with the black tshirt / bag / build factored in.
5. - Person sat on the lower part of the stairs, same haircut and clothing but believe they are older and more well built.
6. - Person leaning against the fountain in the right middle of the photo, behind a woman in an orange dress and to the left of the man holding the orange bag. Looks older and more well-built again.