[SudVolk]

It makes sense that the Monarch, and head of the Church of England, should marry someone of that religion. Would the chief Rabbi marry a Protestant? No, his religion prevents it, and so too does the constitution prevent anyone other than a Protestant from being head of state. If instead the Archbishop of Canterbury was head of the Church of England (which most people might assume to be true), then the Act of Settlement might not make much sense, but then we would have a Church not under the control of the head of state. The best solution would be to have a Republic, and to formally disestablish the Church from the state. That's the way things are heading in any case. We could then elect a president who could be anyone worthy enough (preferably of British Isles descent).