Hi Martin,
Yes that’s spot on, definitely the right way to correct it, the elements you described. To stop the sideways movement its about getting the weight transfer from right leg to left leg in sync with your body rotation and also staying nice and low with knees well bent as you said.
Yes it will take some time but you are doing the right things and you’ll see improvements as you go. Feet solid on the ground when playing the shot is another good way to help this which you mentioned as well. The feeling of the body going forward is great too.
Something else which might help, is making sure your shot isn’t too long and the follow through finishes in front of you and not up too high or across the body. This helps to get your energy transferring forward as well! 🙂
