I've had a few thoughts on this an also read a book by Henry Cotton called "My Swing"- detailing Henry's thoughts of how he swung the club.

What I am seeing in a great many swings, plus in a lot of instruction is this. The backswing involves three processes:

1) Takeaway- is about rotation of the left arm and hand away from the ball to about 8 o'clock.
2) From 8 o'clock, it is about an upward hingeing of the wrists (like the Fryer drill)
3) Once the wrists are set, complete your full shoulder turn.