Ok chort ..
Here is the layout just to be clear on who is sending and who is receiving.
Linux Box ------ > sftp file tx to remote --------> Remote Windows Box
Private Key Key generated from here.
So I have a private key sent by the remote server, as they are the ones who need the files that we send.
I have since asked them to provide a public key for us to use instead of the private. So going by what you stated below they are receiving so they should have the public key ?
This is getting confusing