How to get rid of new input method choice button / empty space

I do't know for what reason, but my android keyboard suddenly had an extra row at the bottom. Contained within it is an input selection button (bottom left), a massive blank space(waste of space) and a keyboard off down-arrow (right). I would like to remove this row but cant find an option. I even uninstalled reinstalled the app and it's still there so presume it appeared as part of an update. It makes typing harder due to having to reach over the empty space. Picture below. 

Please advise!