Great success! I've returned my instance back to local storage, all in aid of reducing costs in other cloud platforms.
I had set up nginx to cache my S3 media in SSD cache space, so now I need to modify that config to do the same for my media living on high-capacity spinning rust.
I know that as a small instance this isnt really needed, but who knows, maybe I'll have a sudden influx of new users and will be glad of having it set up!