One of the advantages of the passage of time is that you keep working at things until you finally figure it out.
As it turns out, the problem was with the .csv file formatting. I am working on a Mac and when I upload the file to the server using Transmit, the mode was set to auto and there was no “conversion” of the .csv file taking place to make it readable by the server. I had to change from sFTP to FTP to allow for Mode > ASCII (Text) upload and it solved the problem.
Underlying this, on a Mac when you save a file as .csv it retains a paragraph line ending or \r and the server is looking for a new line ending or \n
By uploading the file as ASCII(text) it converts the \r to \n and the file then becomes readable by the server.