Delete rating by id or ip?

Hi there,
using your plugin for many years now, thanks for it and the support!

Some time ago a person started spamming our reviews with 1-star-ratings. Sadly it does seem, there’s only a way to get rid of the rating, as long as nobody else has rated, since there’s only an option to delete ratings for an entire post (id). Is that correct or is there a way to get rid of singular ratings (there is an id colomn for it, so this might be possible)? Or could we even block their ip or something?