I have Geany 1.34 and 1.33 with plug-ins on different computers and the Numbered Bookmarks plugin does not work for me.  The plugin is enabled, but nothing happens with the keyboard shortcut Ctrl + Shift + NumberKey. Also I did not find the shortcut keys for the plugin in the settings.
My system: Linux Mint 19 Tara 64-bit Linux kernel 4.15.0-42-generic x86_64 MATE 1.20.1