Hi Jonny,
I am not really sure what effect you are after, but perhaps this will work:
Select your curve (path) with the Node Tool (2nd icon from the toolbox at the left side of the screen)
In the Node Tool - Tool control bar that appears at the top of the screen, you'll find "Make selected segments lines" (11th icon from the left side, looks like 2 nodes connected by a straight line).
- If you need seperate line segments you can also use the tools to break the path where desired, the icons and the tooltips help with that. After that you use "break apart" from the Path menu.
- If you need more accuracy (more but shorter line segments) you can select all nodes, and click the + symbol to add more nodes, and then follow the previous steps.
I hope this helps.
Cheers,
Syllie