How can I create a menu entry for Backbox Tools in KDE Plasma 5

[MarvinHarris]

I've recently installed backbox-tools following the instructions here (https://www.backbox.org/repository).

Once done, I installed backbox-menu as well to implement the xfce menu.

I see that the .desktop entries are created in: /usr/share/backbox/applications/ and the .directory files are available in: /usr/share/backbox/desktop-directories/

I copied the entries from: /etc/xdg/xdg-backbox/menus/xfce-applications.menu to: ~/.config/menus/applications-kmenuedit.menu as advised by a lot of Googling, but I cannot seem to get the backbox entries appearing in the KDE Plasma menu.

Can anyone shed any light on this matter? I feel this should either be easier than it is or I'm being stupid and missing something obvious.

I'm running Kubuntu Ubuntu (https://docsbay.net/ubuntu-installation-guide) 15.04