I recommend giving Clarke's trilogy priority as it was published first and then in 1998 republished as the Toronto Trilogy in uniform editions. What's more, Davies' trilogy was (sadly) never completed. I should add that I'm not entirely convinced that he would have applied the name to the books. Gibson provides nothing more than speculation, writing in his Introduction to The Merry Heart: "he researched and prepared for the novel that would foillow it - to make up what might have become known as 'The Toronto Trilogy'..."