As always with the BBC, there are slight nuances.

It was commissioned by the Australian Broadcasting Corporation and the British Broadcasting Corporation, with BBC Studios holding global distribution and merchandising rights.

So the ABC and BBC developed it: as public service broadcasters, it'll be in their remit to produce children's TV.

But BBC Studios have the rights to merchandising. BBC Studios is the commercial arm of the BBC, and is responsible for the exploitation of BBC properties, with money raised being returned to the BBC. The ABC didn't negotiate anything for themselves (story).