The F*tping end
So it's all working now - turns out it was the Samba configuration was all wrong for CentOS.
Here's an article on setting up Active Directory for CentOS
So it's all working now - turns out it was the Samba configuration was all wrong for CentOS.
Further to that post, it turns out that vsftpd was never working it was OpenSSH that was running the sftp server. Getting vsftpd to work with the configuration we need on our server is more difficult than I initially imagined.
So I've just spent a day messing around with the configuration files and users permissions trying to get vsftpd working on a RedHat install of Linux. There were lots of really helpful sites out there but not one of them mentioned the fact it's SFTP access only by default now. So if you're stumped by that 530 Login incorrect error, when you just *know* it's right, then this might be it.