BBC Worldwide is responsible for output outside of the UK and outside of the TV Licence so I would think BBC UKTV comes under BBC Worldwide.
BBC Worldwide is just one of the companies within BBC Commercial Holdings Ltd responsible for (amongst other things) output. Global News, for example, is a separate entity. There are a few other companies held by Commercial Holdings including BBC Store and BBC Studioworks. The holding company for Worldwide and Studioworks is BBC Ventures Group Ltd.
I imagine BBC Worldwide Australia operates completely separately from domestic BBC so agree with dbl that it's probably unrealistic to expect creative sharing. The sharing of content between Global News and domestic News is perhaps why the former is kept separate from the other commercial entities.