Rob,
I think I have the solution for you, related tracks have changed significantly.
Before you had a window to the right on your screen, where the related tracks showed up (and a gear icon for settings).
It is still there but now for the changes:
You need to create a “related tracks profile” it is done by right clicking on the related tracks bar on the left side of the screen (a plus icon shows), where you find collection, playlists etc.
Now create a “related track profile” to your liking.
When the profile is created, you can select that or other you created in the window to the right where tags info etc. are. Clicking on the link icon not the gear icon. Select the profile you want (from the popup), and you are good to go.
Remember the related tracks only shows up first time in the window when a is track is played.
It is still there but the usage is different, it took some time to figure it out
I hope it solved your problem.
Best Regards
Michael