What a precious postcard!  I am pretty certain that this rare undivided back postcard is the work of Louis Wain.  It was published by Mc Loughlin Bros., who published many books with Louis Wain's art work. I have seen a few  other McLoughlin postcards with Louis Wain's work that were unsigned.  The back is used. The front has corner tip wear.  The front has corner tip wear.  There is a small vertical crease along the bottom edge  under the words.  Good+/VG condition.