We were going to have 12! But the numbers changed about as often as the name of the Project (The Future Frigate, The Common New Generation Frigate, The Anglo-French Frigate, Project Horizon etc).
And the question was asked: "It's an Anti Air Warfare Destroyer, why does it need a flight deck?" Fortunately common sense prevailed
- how else would they get the spares, mail, etc, and when not doing air defence they'd be doing other stuff where a helo is really useful.