How tightly are you each gripping the hand? It's easy to hold the hands too tightly, rather than just using a connection. That can make it harder. I'm a 5'7" woman and don't have too much of a problem; maybe it's our instructors who have prevented it. If he doesn't bring our hands to eye level, then raise it over my head, it's easy to bring it up a bit as I turn.
I also make sure I keep my frame and arm position to prevent injury. The arm crankers are the worst, I agree. It's off-putting to think you have to dance a bit defensively, but after a couple of bad experiences, I've learned. I also agree casually mentioning it to the partner may be a good idea. There have also been times, if something's bad enough that it can cause injury, I'll quietly mention it to our instructor. He or she usually finds a way to work it into the lesson in a few minutes as a reminder to all of us, not singling out anyone.
I went to the link, we're working on WC again in our classes, so it was nice to see a good review. Also, it was fun Robert Royston and Nicola. Love N Dancing is one of my secret vices. I enjoy watching dance movies and while some of the acting's a bit weak, I'll take any ballroom type movie I can find.