I have made a slight modification to the menu items by adding all the different categories into the main menu. A drop-down menu will appear for sub-categories.
The rest of the other pages have been added to the secondary menu, which appears below the main menu.
Hopefully, this will help users, especially new visitors to this site, navigate the site better.
In the old layout, it might not be so apparent that a wide range of topics are covered on this site.