For Example, Victoria, Cannan, Yew Chung (Yew Chung doesn't provide playgroup but nursery), Nurseries of Salavation Army also very full.
I think parents don't have to find the school so early, but they have to plan what kind of education you would like your child to have.
Most of the bilingual schools are very popular so if you like this kind of school you should apply for them as soon as you can or search whether these schools provide nursery or playgroup, becasue it is easier to be accepted their K1 if the child in their playgroup or N1.