Ok I may have worked out my own solution, I'll show it here to let others know what I did, plus any other ideas would be welcome.
I selected my landmass and cloned it to a polygon, this removed the nodes but kept the shape. I then removed the orig…
Unless I've completely missed something I'd love to see a freehand draw tool, useful for tweaking coastlines etc.
Update: Fractal freehand looks like it'll do what I want