Hi
My two also went to the Maples they loved it and so did I. They are now 8 & 9 so it was a few years ago but as far as I know it is still as good. There were two classes at the time the orange class was a good bit bigger than the blue I had one child in each class and both were very good. My kids were very shy (still are) but they were really well minded and learned loads there.
Peter Pan on William St is also very good but is another big one, my nephew and lots of my friends kids go there.
There is a play school in Harmony Heights, one of the first houses on the left as you go in, its been there years and is supposed to be very good.