Some further interactions with the airline have confirmed that my partners ticket should be economy but it will be honored as business class and we have an email stating as such. It's still all showing as confirmed everywhere and no updates have been made to the ticket as far as we can tell, including on the Tianjin Airlines website (they really need to upgrade their website).
But the added complication is that Opodo have taken their money for the card transaction fees but not for the air ticket itself, and the pre-authorisation has now expired.
What would others do? Just sit it out and see what happens?