Bennett have their Accelerate stream (may be spelt differently) and my understanding is that children can be put into this stream/set (whatever
!) from some point in late Year 7 or early year 8 . DC's are Cats tested in the Autumn term anyway, I really don't know the fine details but all the feedback that I have had is positive about all their ability sets.....apart from parents who feel that their dc's should be in the top sets for everything
Have you and your ds looked around the school -did you pick up any of their blurb on the way round?