A lady working in a baby store once told me that a 0.5 tog G/bag was equiv to 1 cotton sheet; a 1.0 tog was equiv to 1 cotton sheet plus 1 cotton cellular blanket; and the 2.5 tog was equiv to 1 cotton sheet plus 2 cotton cellular blankets. Hope that helps. I am also in Perth and in winter dress my DD in a long sleeved Bonds wondersuit and put her in a 2.5 tog G/Bag.