So I found this tool called bisect that allows me to cut a mesh up mostly in square shapes. I s there a similar tool that you can make more circular cuts with or rather a freehand cut tool.
If you need to be very precise as to which surfaces are to be cut, you can create a separate mesh volume, have it be selected with the main mesh being unselected, overlap it with the unselected mesh, and invoke the Intersect tool (look for it using the spacebar search). This will create a cut along where the selected mesh overlaps without merging the two (remove the cut volume and you’ll have your cut).
You can actually use lots of cut volumes if you want (there’s no real limit).
You could use the grease pencil tool to draw a curve in the viewport. In the grease pencil options in the toolshelf you can press the Convert button to convert to a mesh and then use the knife project tool to cut you object along this curve
Thx I will try these out see which suits me best.