They aren't related at all, the haeomvore thingies are psychic mutants from a grimdark future timeline that was created and obliterated by Fenric and the Old One in that very story. MOst of that didn't make it to screen though, even in the extended version. It is in the Curse of Fenric novelisation though. The last of the McCoy era was kinda the inverse of the early Pertwee where they jammed 3 episode stories into 6-8parters, Ghost Light and CurseoF could both have taken at least 6eps to tell properly.