I have noticed answers such as Is there an open source tool to planarize graphs? stating you can use GRASS v.net from within QGIS. However I can't see it - my QGIS processing GRASS toolbox contains 160 algorithms, none of which are v.net.
Am I looking in the wrong place, or has it been removed?
My guess is that is has been removed from the Processing Toolbox.
You can still access v.net from GRASS tools. From QGIS 2.10 onwards, you have to manually select QGIS to start with GRASS, you can do this from the Start menu.
The GRASS menu is available from the Plugins menu:
And v.net should be available in the GRASS Tools: