any good mandarin teacher for private class at home for 2 kids at island east

as title.

we have 2 kids at both age 3 from international schools. they were local kids who can speak a little cantonese. we want to find a good mandarin/putonghua teacher who will be available in weekdays' afternoon (except monday) at one of our homes at island east. the 2 girls have some experiences in learning mandarin as well as reading some chinese words and vocaburies. we expect the teacher can teach them read, talk and pinyin in putonghua/mandarin.