Is it possible to use UINavigationBar to have it displaying a heading throughout the app?
Like some kind of branding of the app (having it show a logo).
Though I’m already using UINavigationBar to to push and pop view controllers.
Or is there someother better suited widget for this?
The way I want to use it is best described in this picture:

From UI quality this is not a good idea to have anything above the navigation header. Avoid this.
As it was answered, you can use any kind of UI widget as title in navigation bar.
The good way to do this is by setting the titleView property of the UINavigationController.
(Default is is customize the title property, that will be changed to a UILabel internally)