Hi, I have two kids at Shaftesbury Park, both in the bilingual stream. I think the classes mix quite well at break time and they have other shared events. If you are waiting for a place in the bilingual class, I would think your chances are very good - the international nature of the bilingual class means people move away/abroad quite a lot.
My experience is that the school is a lovely, warm, happy place for the kids to be, whatever stream they are in. The teachers know each individual child well, despite having around 30 kids in each class.
If you have any specific questions, feel free to message me!