I ended up rethinking the perspective on the left of these buildings, and getting some order to them. The other changes I made were to the windows just trying to get a better balance.Next I felt I needed to lift the section of the picture that's under the bridge, so used some cadmium yellow and orange in the near foreground, then took it back to mould the form of the boat, and then also to depict the lit water reflected on the bridge's arch.
The other change was to soften the shadows, to show the true colours of the walls within the shadows.
Now I need a title, so far only thought of 'Boat under a Bridge', which is descriptive but not very imaginative. I don't need to decide for a few weeks, when it will make it's first appearence in public at a Spring Exhibition, along with two other gouache studies of the same bridge(these also need titles!).