My project's forks have been moved to another fork - how to get them back

I briefly made my repo private. (My mistake - I thought I was making a project private).

The result is that the ~250 forks of my project (fisharebest/webtrees) have been moved, and are now forks of one of the existing forks (jon48/webtrees).

This obviously screws things up for these 250 users.

Is there anything I can do to reverse this?