The one at Choa Chu Kang Center building. Next to Lot One. The teacher will change when the kids graduated to the next level. I had no issue with any of the past teachers teaching them.
I can resonate with your struggle to practice flashcards with the young. Time and energy are much needed.
I'm currently on a small project to ease the effort for home practice. Hope you will find it useful.
I had good experience sending both my kids to Heguru and Shichida too. It is expensive and I still feel it is worth it.
Of course, the home practice matters too
Ps: I still vividly remember the home practice on the Element table thingy :D