Where in Hong Kong do you stay? I live at the Central. I can list a few in my area here. The ones that top my list are: OWN Academy at Sheung Wan, Starlit voice in Kuwloon, Foundation Academy, Twinkle Dance in Wong Chuk Hang, Flex studio (they have two studios in Central and another in One Island South.)
There are certain schools too which offer great summer camp options for kids this year. I think you should consider them too. Some of the famous ones are Kellett School, Woodland Preschools, Safari Kid, Eton House, and City Kids.