Paul, that sounds a bit like the setup I was taught in my first few lessons of golf. How my instructor at that time tried to teach me was to straight out both arms like wings of an aeroplane, and then get the bent in the waist and butt sticking out nicely. (By the way, that was at Peter Senior and Gary Edwin academy).

I felt that was quite a one-plane swing they were teaching. And a bit of that rubbed off on me, as somehow I developed the habit of swinging really flat and open. If you remember, I was kinda stuck in between the One Plane Swing and Two Plane Swing, and lately I have gone back to a more natural 2PS for me (ie. bringing the arms up) and tried to correct that...