Another update and a few words about method :

I work down the page from top to bottom, laying down areas of tone and then building them up gradually. I consider the upper part now to be finished but i may need to go back and strengthen some areas depending on the overall drawing appearance. As you can see i have filled in all the areas of water towards the bottom of the page. I find it helps psychologically to cover large areas like this so I feel like I'm progressing and I'm not working on blank paper. I will build up the shading in subsequent passes.