"Of course Charles II had a lawful heir, his brother James, who was also a son of Charles I, as Rapparee said. Chucked out by a military coup for seeking to end religious discrimination against Catholics and other religious minorities. Very foolish of him, of course."

Quite I didn't word it as best as I could. It was the brother of Charles who succeeded him not his son which is what the original claim was. James wasn't the fair minded non-religious bigot that some point him out to be though. It is not as simple as that. Prior to being king he run Scotland in the name of his brother and persecuted the Presbyterians. The period known as the Killing Times. When he became king he sought to lift the oppression against Catholics which maybe isn't surprising as he was a Catholic himself - however he initially hardened laws towards the Presbyterians. Not the brightest button really. Even if the Episcopalian advisers did finally advise him against the worst excesses against the Presbyterians - seeking equality for a small religious minority (ie within his Scottish kingdom) whilst at the same time actively persecuting the sect who probably had the largest amount of adherents north of the border wasn't a sensible strategy.

As to lawful heir well that depends on what you believe. When they put their cases to the Scottish parliament the attitude of James seemed to consist of he had the Divine Right to rule because of who he was and everyone should just bow down and do as he says whereas William and Mary accepted (possibly not all that enthusiastically)that there were some restrictions on royal power. Even in the time of Robert the Bruce it was accepted (ie Arbroath Declaration) that in certain circumstances the king could be removed.