If they do this, won’t the Windsors have to hand the throne to the Wittelsbachs? They have a better claim based on descent from King James I. George I became king in 1714 because he was the closest Protestant cousin to Queen Anne, but there were a number of Catholic relatives who were more closely related.
The Stuarts in “exile” in France would likely have an excellent claim. But Possession is 9/10 of the law and you won’t see any change.