On second glance it looks as if the shop in the picture (corner of High Street) is pertaining to be the post office as there is a post box on the side... But I'm puzzled if that is the case as to why call it Causewayhead Post Office when it is in High Street.
I remember a "directory" of later years produced by a Mr Pengelly(?), I have a vaguish idea that it was uploaded by yourself a while back. I cannot find anything at the moment in the flat. I will eventually be able to function, but I do know that I have many originals in the "spare room".