I have created a language file in poedit for the use of the PHP gettext function, now on the page I am trying to test it on, I cannot get it to find/load the .po or .mo file
I suspect it's your path.
Is "/includes/locale" the correct directory on your host? Or is that relative to something? Note: you need the full pathname, not relative to your home directory or the install directory. so that might be something like:
What is the full directory where it's found?