Tonerre the children at Michaela are actually happy! People who have visited the school, including Boris, have been impressed by the atmosphere in the school as well as the children's knowledge.
Well, yes, when the unhappy ones have been driven to leave, that is the impression you will be left with.
As for Johnson's views: really? Does anyone seriously believe that when he visits a school like this he is going to say anything negative, or indeed be allowed to see anything negative?
True story: some time ago, when he was Mayor of London, he was due to visit a school near to me. There were a couple of kids who had been illegally excluded but who, after threats of legal action, were due to return on a certain day. A couple of days earlier, the school contacted the parents in a panic and asked if they could return a day later. When they opened their local paper the next day, what should they see but a large picture of Johnson on an official visit to the school on the day the children had been due to return.