Apparently Sayers' heirs and publishers felt that way, too, although the relatively recent Jill Paton Walsh Harriet and Peter Wimsey mysteries struck me as rather unsatisfactory attempts to produce them. I think the first one, "Thrones, Dominations," which consisted of an abandoned Sayers manuscript that Paton Walsh completed, was better than the ones Paton Walsh wrote from scratch, but I don't remember anything else about it.