Update

We went with centre B. We went this morning and he played and then didn't want to leave and all the staff were charming as usual, and ... I'm still riddled with uncertainty. What if this isn't the best one for him? What if he's unhappy because he really did prefer the other centre? What if ... what if ... what if???

Pfah. 

If we fast forward two months, I'll be wondering why I spent even a single second worrying or second guessing. First of all, it doesn't help. And second of all, look at him! He loves the place! It's all great!

... I hope.