Hi Liam,
For exporting data to a proprietary format, we advise developing a dedicated plugin. Plugins are a way to extend Dataiku DSS with new capabilities by packaging custom code. You can have a look at our learn section on plugins: https://www.dataiku.com/learn/guide/code/plugins/writing-your-first-dss-plugin.html
For an example of how to write a plugin to export data to a new format, you can have a look at our public Tableau plugin: https://github.com/dataiku/dataiku-contrib/tree/master/tableau-export-v2/. We would be very happy to have you contribute a new Qlik plugin to our public plugin store: https://github.com/dataiku/dataiku-contrib#contributing
Cheers,
Alex