I use merino kids sleeping bags as well, one for summer and one for winter. They are more expensive than grobags but they are made of merino wool and they have two sizes only, 0-2 and 2-4 yrs and no togs, just a summer >18 C bag and a winter <18 C duvet bag. Not sure if they sell them in HK but go on to the website, they do specials all the time and it's cheaper to buy two bags at one go.