Deleting a flag but still exists in Search API index it kills the whole site

I have a number of flags, i deleted them from the views they were in so they weren't seen on the front-end.

I forgot to remove them from Search API index fields as i use them to be searched on and when I go to delete the flag the whole site goes down.

I have to restore the site to a previous backup and can't see the logs or any error reports because of this but this is the only remaining flag config i can think of on my site that remains as I delete it in Structure > Flags