After receiving feedback from my tutor, I feel more certain that landscapes are the direction I wish to go in for this project. Julian felt that the idea of 'feeling left behind' in the landscape is rich conceptually, and is being effectively communicated through my mark making.
I agree that it is particularly important for this project for me to continue making site visits and creating work on location so I can try to convey my direct experience of the place and deepen my connection to the subject matter. I am planning more site visits in the near future in order to do this.
I'll also, as suggested, try working on some different toned grounds and experiment with layering and translucency, as well as reductive methods of scraping back, erasing or lifting the material.