Changes to royal succession rules in GB.

All Commonwealth realms have agreed to press ahead with a bill ending discrimination against women in the succession to the British throne. Why?
Not why should a bill be necessary. Why should they even be consulted particularly when the largest of them all continues to flirt with the notion of becoming a republic? Put another way, what would the reaction be in these Commonwealth realms, if a similiar edict affecting their own constitutional affairs were to be issued from the bowels of Whitehall? Just a thought.