Ok, seem to be having some problems getting this to work.
I started off by dragging the contents of Example 7 into my project and then changing all the settings so it fit on my screen. Everything working as expected up till now. However when I change the horned helmets to another sprite in a different atlas, those sprites always shop up on screen.
Can't seem to figure out why, after all, all I have done is simply change the atlas on an exciting sprite.