7d. They seek to change peoples's minds (13) ??Y?????R???S
11a. Sole representative of this kind of flower (8) ?L??????
13d. Gave a signal but grew languid (7) ??A?G??
13a & 6d. March will provide a defnite time for his movements (4-7) ??O?-??L????
Clues 11A and 8A have got mangled. Swap their second halves over and you get 11A 'Sole representative of the kind of marine life' (answer - flatfish) and 'Ardent feeling for this kind of flower' (answer - passion). I wonder if they're going to make a habit of this.