The method you described works just fine in an area with a fairly level horizon StuartUK.
However once you get the picture and the feel and the sound of a good steep turn you can then practice your steep turns with reference to the altimeter to maintain a constant altitude that results in the bang you feel when you hit the wake the airplane made where you stared the turn.
After that gets boring you learn the picture sound and feel all over in the inverted position.
