I am looking to replace a mattress because it is a double and 10 inches deep and a pocket spring it is impossible for me, as an old person to manoeuver. I know that there are mattresses which are no turn, but they still have to be rotated and given the weight and depth and end of the bed frame this is actually harder to do than attempting to turn it over. What is the lightest and most shallow mattress but of good quality please? This didn't used to be a problem when mattresses were bonnell springs and 8 inches deep.