I read that and thought it was a bit too frank to be out there in the open. If a parent from that school stumbled accross it I'm sure they could identify their school and the children involved. That seems particularly unwise from a headteacher. I am left hoping that it is fictional based on experiences over the last few years mixed together, rather than an actual diary style blog.
agree - some people don't realise that it can become easy to identify schools / people etc through blogs - they need generic characters and recurrent stories eg one of the good medical ones has Mrs Anxious, Mr Spleen, Mr Colon, the Commando, Mrs Frequent, Mr Enormous, Mrs Bloat, Mrs Demanding and Mr Ouzo - regular characters and with stories which are an amalgam of experiences.