School (Abu Dhabi)

Good Morning,

My husband, 2 children (6 and 7) and I will be moving from Italy shortly. Children speak English and Italian fluently. I have been searching schools for our children and am aware it is difficult to get into the good schools. My question is: is it really that hard to get into the schools? Is it possible to join the school part way through the term? What are the know as the best "educational" schools (not too worried about how many pools they have etc? When is the latest possible time to enrol?
Thanks so much for any advise you can offer.
Rachel