yes exactly, but the situation is very unclear especially about which features is reliable or not to exclude any hybride, maybe some of the features especially about head pattern and streaks on breast are just a case of moulting issues. The underwing pattern suggests that this bird has strong Western Marsh Harrier influence, and it could be possible that this bird is simply just a Western Marsh... As Paul said, good pictures showing the rump may be of great help to better document this bird.