I personally prefers Woodlands rather than Boxhill. But of course, your best bet is to apply to IS at reception / Kindy/ petit and start from the beginning. Then you are securely staying there for a while.
Well... I would say schedule a school visit and you will get the feel of the school. You'll know what I mean. In expat world, Woodland is rather famous. But personally, I would go to IS since kindy if you want to go to IS... less competitive.
my son is studying in ma on shan boxhill. i found most of his classmates communicate in english. after studying for about 1 years, his english and mandarin speaking ability improves a lot, and we can appreciate his sprogress.