Hi Paul
Thanks for posting. It’s best to take control of your menu and add pages manually as required. Head over to Appearance > Menus
and create a new custom menu. Once created, add the pages you need and then save the menu to the theme location you want to display it at. You can have as menu custom menus as you want in WP, they will only display once you save them to a theme location. Drag items one level deeper to create a drop-down menu.
Let us know how it goes.