Most such functions have been moved into the relevant panel menus/ context menus and the buttons removed to make the interface more streamlined - whoever came up with the idea.
This hasn't been removed. The menu is still available by clicking the composition name in the tab. All that has changed is that the "hit" area for invoking the menu no longer includes the part of the tab that includes the word 'Composition'.
Thanks guys. Seems like the easiest way to bring up extra comps is to double-click the required comp in the project panel, which granted is easier but not necessarily obvious... We live and learn!
Now, why have the comps thumbnails in the project panel been made monochromatic? Finding the project panel more difficult to 'read' at a glance. Bring back the colourful comp thumbnail please, or at least an option of having it like the old version.