I don't know about you, but i have been trying to find the rest of these sermons for a long time:
Saint Gregory Palamas: The Homilies, edited and translated from the original Greek, with an introduction and notes by Christopher Veniamin
I am not a salesman for the publisher, but there is a significant discount for ordering before this Wednesday.
(PS. Do not worry that they call it "The scholar's edition: for priests, theologians and the educated layperson", that refers to all the notes, (200+ pages), the sermons themselves are in plain enough English.)