Hi Leanne,
This is a good location and the vibrant treatment, combined with the water on the bluestone pavers looks great.
As you make a photograph though, it is reasonably important to ask yourself questions about why you are placing a person or a subject in a certain position. More often than not the questions you should be asking yourself are the same questions that your audience will also be asking as they look at the photograph later on.
In looking at this photo I want to know why your son is standing in front of this particular artwork? Did he or his mate paint it, in which case are you treating this as a portrait with his artwork? If this were the case then the treatment would be more than appropriate.
I do not think this is the case though, which is why I would be more inclined to treat this photograph as a streetscape.
I feel that this is a sort of scene that we would typically pass without ever stopping. That is why if I were making this photograph I would be more inclined to have your son walking nonchalantly past the camera rather than posing next to this artwork. Keep everything about the photo the same, including the composition and the exposure, but have your son more towards the right of the picture, and possibly just half the distance away from the camera.
This would create an interesting disjoint between your son and the location and I think people would not struggle so much with whether this image was trying to be a portrait or a landscape.
I hope you at least enjoyed your day in the city despite the rain!
Cheers,
Anthony