Hi James,
I take it when you say 6 iron and up you mean a 7, 8, 9 etc ?
If that is the case then you should indeed be hitting down into the ball with these
irons, although you only need to have the ball placed midway between your heels (Not toes). To ensure you are striking down allow your weight to favour the front leg as the
irons get shorter, you can do this by positioning your sternum (chest bone) a little ahead of the ball.
Your club will bottom out just inside your left armpit for a right hander so the position I have just explained will allow the club to strike the ball on a downward arc then hit the ground making a divot just in front of the ball.