I would recommend Science Heuristics.

http://www.scienceheuristics.com.sg/programmes.htm
My P6 girl is good in science, but bad at constructing the answer. She attended their holiday intensive class. It was very compact. She learns how to apply the concept and using essential words that helps to express her answer clearly. Her answer can be 3 lines, with the new skills she just needs a sentence or 2. I feels that this is an essential skill that can help her even in the Secondary Edu.
Science tuition is essential because she had encountered few teachers who can't finish the syllabus in time or rush through the lessons.
Hope this help.