Sequence your spine correctly during the backswing, rather than your hips and shoulders, by using this rotation exercise
Play the ball off your front heel, open the clubface to one o'clock, balance slightly on your front leg and make sure you swing down and through to the left. The key is making a non violent full swing, splashing the ball with an oval area of sand out of t
In the one plane swing you bend more from the hips, your arms are hanging down and swinging around your chest and your finish is more rounded. It is easier to maintain because there are fewer moving parts than the two plane swing.