I spent a good few hours tracing out the exact route, which I now have identified, and then went to get my hacksaw to start removing the old copper. Ah... the hackswa was at home.
So, instead, I spent a couple more hours cleaning out the bilges to make access to the pipework easier when I return with a hacksaw.... Its amazing what you find when you look.... Currently, I've found a large danforth anchor that I knew about.... a large Fishermans anchor that I didn't know about, and about 40m of chain that I didn’t know about!
Further to that, another few kilos of redundant wiring removed.
Almost at the stage where I can start painting the bilges...