Unfortunately I'm not an expert with Network Manager, until now it remains a mystery to me how it works, where is the configuration stored and where there heck are the log files?!?. Nevertheless, if the "Network Manager" icon disappeared, you can run that "Network Connections" tool directly from "search your computer" (click on the ubuntu logo on the top left or press the "windows" key) and type "Network Connections". Alternatively you can run nm-connection-editor from the terminal. On ubuntu, it is part of package network-manager-gnome.
Graham,
Unfortunately I'm not an expert with Network Manager, until now it remains a mystery to me how it works, where is the configuration stored and where there heck are the log files?!?. Nevertheless, if the "Network Manager" icon disappeared, you can run that "Network Connections" tool directly from "search your computer" (click on the ubuntu logo on the top left or press the "windows" key) and type "Network Connections". Alternatively you can run nm-connection- editor from the terminal. On ubuntu, it is part of package network- manager- gnome.
Nir