There is one at 利源東/西街 selling Korean children clothes. Comio (Times Square/Ocean Terminal), is also rather型, but expensive. Bubble Gum at Ocean Terminal is quite good too.
This is next of Nail nail, just upstairs of shatin railway station. If you have member card, it should have discount. And they have adult garment as same as the kids wear, match as mother and son outfit. :D it's cute!