My DD is starting at the Stepney Tree Tops in January. We also had our name down at the St Peters Community one on the same street but didn't get in (apparently they were already struggling to place siblings who have priority).
I actually preferred Tree Tops when we visited the Carers were very interactive with the babies (DD will begin in baby room) and friendly, the other place didn't have that feel to me. The way they structure the day seemed really good to me but I have no previous experience in this area.
We only had our name down for about 4 months but called regularly to enquire.. I knew the director was doing allocations in November and rang then and she said she will fit us in.
The only downside, is that the outdoor area is artificial grass with sails for shade (which is fine), the St Peters place outdoor area was huge with lots of trees, natural shade etc but the kids can't go outside when it's too hot or raining anyway.
So I would keep phoning every couple of weeks. Good Luck!!