Can anyone recommend the best videos for learning to turn?
Thanks
Why a video? I learned to ride, freemount and turn without ever doing any research on unicycling. Just swing your arms and/or lean. Once you learn to hop you can also turn that way too.
The scientific explanation can be found here:
translation: “I don’t want a video, so why would you?” 
translated translation: A video isn’t required and won’t be a substitute for practice.
Really, the basic stuff like staying upright and turning are things you learn down at the muscle memory level; I’d compare it to a little kid learning to walk and run. There isn’t much useful teaching to be done; you just have to do it until your muscles have it down.
There are tons of unicycle things where technique does matter - learning something like a rolling hop is more like learning, say, a good tennis backhand, than learning to walk, and once you get to that point some instruction would probably help, and it’ll be time to hit youtube.
Because videos are an acknowledged way to enhance learning, together with actual practice.
What they said.
I also looked for videos/tuts when I needed to learn to ride straight, which is basically turning when all you can do is turn left constantly. Nothing that I found really helped. The closest thing may have been the physics video embedded above, though I couldn’t make the countersteer thing happen directly; it came about as a consequence of the method below.
To turn right, twist your upper body to the left. It is most effective if you have your arms outstretched, for reasons explained by simple physics. It is unsophisticated, wears your tire, and, of course, you run out of twist until you can reset yourself, but once you can control your direction that way, you can work on making it more of a lean in the direction in which you want to turn than a twist the other way. And you always have it to fall back on when you need to turn more quickly than you can by leaning.
This is like riding. Well, it’s part of riding, but hopefully you know what I mean. You need to develop muscle memory, which is not in the part of your brain that thinks. The twisting method gets you to where you need to be to develop the skill to turn by more subtle means.