Lucky you. For large volumes of food waste BSFL can be a way to go. Yes I would just keep adding the cardboard. I am a bit worried the BSFL have created conditions not happy to worms. Can you gather up a quantity of worms for a temporary bin in case when the BSFL leave there are not worms left?

Worm bins are BSF magnets so if they're native to your area about the only thing you can do is put the bin inside a screened enclosure to prevent the females flies from laying eggs.

The Black Soldier Fly Blog forum has a discussion about this (link below)

Here is a link that might be useful: Black Soldier Fly Larvae in Worm Bins