Didn't Disney own Power Rangers/Saban at one time? Although thinking of that, it wasn't until years after Power Rangers started.
They did but now they don't own Power Rangers; it was bought off them in 2010 and the franchise ultimately went to Nickelodeon where they're apparently sticking together until at least next year. Disney apparently owns the rights to most of the Saban back catalogue with the exception of Power Rangers, the two Power Rangers films, Digimon and a couple of other films.
Not quite right. Disney bought Saban Entertainment in 2001. They wanted the Fox Family channel which Saban owned, which became ABC Family and then recently Freeform, but acquired Fox Kids (which became Jetix and then Disney XD) and the Saban programme catalogue as well. Saban Music Group, however, was not part of the deal. In 2010, Haim Saban launched Saban Brands, as part of a larger Saban Capital Group that also included Saban Music Group. Saban Brands' first acquisition was Power Rangers, which Disney had recently cancelled (that's why 2010 is the only year since it launched without any new episodes). When Saban signed a deal to get PR onto streaming services and DVD, they knew they might be an audience for their other similar shows as well - so they went back to Disney and asked if they could buy back BeetleBorgs, VR Troopers, Masked Rider (that series hasn't been re-released but it's rights are needed for three backdoor pilot crossover episodes in Power Rangers), Ninja Turtles: The Next Mutation, and Digimon. I'm not sure if they got Mystic Knights of Tir Na Nog back, as that one hasn't been re-released. Nickelodeon (who bought the Turtles franchise at around the same time Saban bought back PR) only bought the airing rights for Power Rangers. They still air it in America, but Nick UK quickly ditched it, new episodes now air on Pop instead, with reruns on it's sister network Kix. The Power Rangers movies were never owned by Disney - they've always belonged to 20th Century Fox, in the same way that the new one out next month belongs to Lionsgate.
GMTV airing Power Rangers had nothing to do with Disney's part ownership of GMTV originally, but ITV dropping PR after Disney's last season RPM is probably not a coincidence.