BBC Symphony Orchestra
I downloaded your patches for BBC Discoverstation, however, I have BBC SO Core not Discover as I paid to upgrade to it. And it fails to load because my BBC SO is on an external drive. However, when I go in and swap instrument select BBC Symphony Orchestra from my AU list it selects it and allows me to select any BBC SO core instrument. That means that your patches work with BBC SO Core as well as Discover. So you might want to rename the Discoverstation to BBCSO 6 instruments. However, I can only load 6 instruments for an ensemble at a time and therefore cannot create strings, brass, woodwind ensembles which would be useful if the patches allowed you to do that. Or I just do not understand how to add the layer.
We plan to work with Spitfire on adapting DiscoverStation for their SO Core and other BBCSO plug-ins, but not until after the library is completed.
I'm not sure I fully understand what you wrote, but I think you're saying you can swap the BBC SO Core plug-in (which works) for the BBC Discover plug-in (which does not). This would load a fresh instance of BBC SO Core, without the state-data (instrument selection and all settings) that was saved in the original DiscoverStation patch, so this won't work as a way to adapt the patch for BBC SO Core.
To learn about adding layers in Unify, check the manual page https://pluginguru.net/unify/manual/doku.php?id=first-patch, and also the Unify Video Manual video series on YouTube, specifically video #3: https://www.youtube.com/watch?v=mn2IXvfHGbI.