Swinging in a phone box

Hello all again,

Well I've had a couple more lessons now, but my instructor is saying I'm still swinging like I'm in a phone box. By that he means I am bring the club up too steeply, so when I'm at the top of my swing I would look at someone stood behind me through my arms rather than over them. The trouble is I find it very difficult to swing back in an arched movement.

Even using the Explanar I tilt my hips rather than rotating them. Has anyone else every started out with this problem before, and if so can you recommend any exercises which will help me learn to rotate my hips rather than tilt them. It sounds so simple in practice, yet in reality I seem unable to do it.

Thank you again.