Hi Jack.
I commented on the SO question, linking to a similar one... — maybe that helps.
I think the bottom line is that you want to include an additional form encoding the extra URL params — SO THAT when the form is submitted those get included too.
I don’t think this is tricky per se, but it’s not something that’s provided out of the box.
I think it would make a good addition to django-filter (I don’t often say that :) — if you wanted to hop over to the discussions on the repo we could start a thread, beginning with the SO issues, and the DRF helpers, and then we could look for prior-art (people have done this) before planning a feature.
Kind regards, Carlton