[infinity85]

I'll probably have to send this back as none of the buttons work after I connect the hub to Libreelec using bluetooth

At first put away all you custom mappings, if there are any, then...

Try this pairing guide: http://forum.kodi.tv/showthread.php?tid=...pid2514264

Also, for LibreELEC choose the profile:
Manufacturer: Microsoft
Model: KODI

After you evoked the pairing process through the Smartphone App, you need to go into LibreELEC configuration, enagble the bluetooth service, and then to Bluetooth tab and after round about 30s the "Harmony Keyboard Device" should appear. Press "Pair and Trust".