It occurs to me that a possible approach that may be taken by Mrs Gumley Mason will be to try and pass off the ISI's criticisms as relatively minor, that they have all now been dealt with and there is no more reason to be concerned.
But consider this, The criticisms in the published report are the ones the school got upset about. So upset that they obtained a High Court injunction to prevent publication. High Court injunctions are neither sought nor granted casually. So they managed to persuade a very skeptical and hard-bitten judge that this was a really serious matter and that the school would suffer irreperable harm if the ISI report were to be unfairly published, and that they had a reasonable chance of demonstrating that the ISI's report was so unfair that no reasonable person could have reached the same conclusions.
Well, it has now been published, still containing the same criticisms. From the tone of Mrs Gumley Mason's accompanying letter, it would appear that they were hoping that nobody else would notice how devastating the report actually is.
I suggest you treat the crticisms in it as seriously as the school did when they initiated the High Court action.