As in other BBC prehistorie documentaires, some CGI models are recycled from previous productions to save cost. In "The Giant Claw", the Saurolophus and Tarbosaurus models are a recolored reuse of the Anatotitan and Tyrannosaurus models from the final episode ("Death of a Dynasty") of Walking With Dinosaurs (the Saurolophus also adds a small crest at the back of the head). The iguanodonts from "Land of Giants" are a reuse of the Iguanodon model from the Walking With Dinosaurs episode "Giant of the Skies", and the pterosaur from "The Giant Claw" (identificeert as Azdharcho on the BBC website) are a reuse of the Quetzalcoatlus model from "Death of a Dynasty" (itself a modificeer version of the Ornithocheirus seen in "Giant of the Skies").
It is left to our imagination how Nigel and his crew traveled back in time. In the spin-off series Parque Prehistórico (2006), he does this via a time portal, though even the workings of that are never explained.