Search Taxonomy Term pages containing entity referenced nodes
I stumbled upon a module called Search by Page Paths which swerves the above issue by indexing the front end of the site. This approach means that regardless of the source of my data and where it is placed, it will see anything rendered out onto a page as part of that page.

The main caveat is that one must specify paths to index, but in terms of my particular build this isn't a bad thing and means I have complete control over where a user ends up after searching.