Sam,

You also might want to check your ball position. With out a ball, Strike the ground with your natural swing. Make sure to take a divot. If it looks like a backward letter c you are closing the clubface at impact. If the divot is straight like a strip of bacon then the ball may be to far forward and the extra distance the clubface is traveling is causing the hook. I couldn't suggest an answer with out knowing this.

Golfbald