Hi John,
Milford Sound is a wonderful destination. My wife and I were in this exact spot early in 2014. The only difference was we each had our own boat – five-metre long sea-kayaks! I'm betting the service was better on your boat!
Anyway, this is a great photo and the only thing I really wish I could see more of are the edges of this picture. Ideally, I want to see the passengers all along the foreground of this image. For this simple reason I am wondering if you shot these three images in the horizontal or the vertical?
At a guess, I'm going to say 'horizontal'. Next time, try holding the camera in the vertical format (with the lens set to the 18mm position) so you can include more of the foreground and the skyline in the frame (although it would be difficult to get the top of Mitre Peak in even then).
The only problem with shooting in the vertical is that you need to take more images, and ideally you want to be generous in the overlap.
The advantage of shooting in the vertical is that you will get a larger file and you'll have more room to crop.
The only other concern I have is the post-production technique (is it HDR?) that has put dark patterns onto some of the details in the images. Maybe ease up on that.
Otherwise, this is a great image. As a Kiwi I can tell you that you scored a day out of the bag for this image. I bet if you go back the next time it will be raining!
All the best,
Anthony.