Thanks Allister, tried this but no error message that could help me resolve the issue. No problem with getting the app from iTunes and importing into Configurator, just can't import the spreadsheet with any redemption codes.
Email Apple Australia VPP support, 3 days later got a response pointing me to their basic help files, totally ignored my question and fault completly.
Called Apple Education support, they can't help as its a VPP problem, transfered to them, they can't help as its not an issue with the VPP site but with Configurator. They have informed me the only support is via the email i've already used, which was useless.
So huge phone circles and nothing closer - couldn't even get anyone to understand the problem, they just want to forward my call to other departments. So it appears in Australia Apple Support have no idea of this problem.........
So no closer to a solution. We might try the configurator on an older MacOS machine and see if we can supervise our devices from that. Will let people know how we go....