I've seen a similar shot in a UK photography magazine taken in the exact same position but it was taken at dusk with lights reflecting off the sculpture which added that something different. I wonder if you've tried to emulate that same image or if it is just pure coincedance? Either way, the fact I have already seen what CAN be done with this shot has done nothing for the way I see this image. Sorry!
I think if you would have moved over a few steps to the right the image would have a better presentation as I find the sun dial blocking th subject of your image distracting. The other technicals like color, contrast, etc are all very good.
It seems like there is too much going on...you need to choose a focal point. Is it the Tower Bridge or the sun dial? They are competing with one another.