I've figured this out, but can't see how to delete the question. Thanks.
We have a requirement for REQUIRED METADATA MISSING not to completely overwrite our custom coral tag.
I've identified /apps/dam/gui/coral/components/admin/contentrenderer/card/common/card-banner.jsp as the controller of the banner (overlayed for us due to our custom card banners)
Any ideas on how to display both? A different coral component?