So why is it not streaming here do you think? Someone else must have the rights?
Back in the classic era of licensing, when Bandai went under, Funimation acquired a package deal of titles from Sunrise and Kadokawa, and they were mostly US/CA only.
The Sunrise titles in the deal were Cowboy Bebop, Outlaw Star, Vision of Escaflowne (& Escaflowne the Movie), Code Geass: Lelouch of the Rebellion, Code Geass: Akito the Exiled, My-HiME (& My-Otome), Angel Links, Banner of the Stars (& Crest of the Stars), Witch Hunter Robin, and Tales of the Abyss.
As you could probably tell by some of the titles on there, they were all region A only when they were released in the US. And I remember this stuff because I joined the anime community in 2012-2013 time just as Anime Limited started licensing UK titles and license rescues were a big thing. Anime Limited has some of those and KAZE had Code Geass before it eventually shifted over to Funimation UK. In other words, currently no one in the UK owns Angel Links, My-Otome, Banner & Crest, Tales of the Abyss and Witch Hunter Robin.
Sentai also had a similar package but they barely released any of them except for The Big O (with Discotek rescuing s-CRY-ed).