Unfortunately all of the training schools in Haikou serve both adults and kids, with kids being the bulk of their business. So none of them will be able to guarantee no kids classes. I've worked in several and will not do it again.

If you want to get in touch with the Haikou expat community for further info and leads you might try posting on the Haikou in Englisg Facebook page, which should be easy to find with a simple search.

I'm an admin of the page and it's a good and helpful community.