It's the standard Google media player, I thought that winamp would solve the problem, but that made no difference.
Nothing is being sorted or re-arranged in the folder structure, it's almost as if it's creating a playlist.
I use SwiFTP on the device and send the files over my WiFi connection via standard FTP.
It all reminds me of the stupid gallery app which ignores folders and re-arranges all images on the device in some entirely ******ed way that makes no sense.
I'm guessing it's designed to make life easy for people who haven't got a clue what they're doing, but for me it just causes headaches....