I've just had to reinstall Windows 10 on my home PC and download Office365 (home) again. I'm sure last time I did this it included OneNote 2016 but no sign of it this time. I am aware MS are phasing this out so I'm guessing that's the reason. Anyway, I am trying to get used to OneNote for Win10 (even though my first impressions are that it feels quite stripped down and looks less professional).
There is one thing I just cannot live with, and that's the way the Notebooks/pages/tabs navigation are now laid out on the left. It's HORRIBLE. It takes up so much more space on the screen - the way it was laid out in OneNote2016 was far superior in my opinion.
Please tell me there's some way to change this, because I've had a look and I fear it's not possible.
I’m not aware of a way to change this currently. I do see quite a few different navigation related feedbacks on UserVoice so I would suggest looking through them to see if any meet your needs. If so, vote them up but if not you can create your own for the product team to see.