If I pull with the left side only it feels as if the clubhead is whipping through impact, but also can feel flippy and disconnected.
So mainly concentrating on getting the right arm/shaft looking down the target line after impact and keeping a connected shape(difficult to explain) - getting some pulls when right side gets too involved, some fantastic down the middles to.
Your upper body action is fine so the question is "Why did you pull?"
The answer is because you rotated around your back hip. On the backswing your back hip stays stationary and your front leg bends and your front hip moves toward the ball. That means you have straighten your front leg on the through impact bring your hip back very fast not only to square but opening it wide open causing the ball. One cause of this is that at address your don't have your hips rocked forward. If you have your hips rocked forward at impact it's much harder to ever pull a shot.
The cure is to rotate around the front hip on the backswing not the back hip. Check out the Symple Turn ******************************simpleswing.forumco.com/topic~TOPIC_ID~1192.asp In order to practice doing the Symple Turn LOCK THE FRONT LEG DEAD STRAIGHT. Don't bend it at all. Then do some practice swings and feel the back hips opening up on the backswing.
To force yourself to do this try hitting some balls with both legs locked dead straight. Keep some spine tilt by shifting your hips forward. You'll then be forced to open your back hip to turn at all during your backswing. Make sure your back foot is well flared to make that hip turn easier. If you don't really flare that back foot then the hip turn is very difficult with straight legs.