As an ex driving instructor, the pull push method is not a requirement of the driving test and hasn't been for over 10 years. You may cross your hands to turn the wheel as long you are always in full control and never let it slip/spin back. You must always have both hands on the wheel when driving in a straight line unless you are changing gear or using any of the controls. Pull push is better for new drivers initially, but once any of my ex pupils got comfortable I would tell them the above and then leave it up to them. Some would adapt to suit themselves and some would continue to pull push.