I don't mean behaviour which harms other pupils, such as bullying or failure to observe safety rules in laboratories and workshops, but common things like breaches of school uniform, not using the right entrances and exits, and doing these things day in day out.
Another thing we pick up in appeals and complaints is teachers over-reacting to 'impertinence' from precocious children which often amounts to knowing more than the teacher and not having the sense to conceal it.
Some of us think the staff are very touchy: they often tell individual governors that the head has a bullying style. They also say he is unfair in making appointments, choosing wording in vacancy notices that excludes those he dislikes.
First, I think an independent tribunal might also find it hard to condone permanent exclusion for the kind of offences you describe.
One of the most disturbing experiences for a school is to have an exclusion overturned. A school must also be careful not o miss a genuine problem such as learning difficulties or a seriously inadequate home.
But if, as a governing body, you haven't set out guidelines on the relative seriousness of offences, your behaviour policy badly needs review, and you might also beef up your home-school agreement.
I have also heard about the kind of teacher who finds it hard to cope with very clever children, but being bright doesn't excuse disrespectful behaviour. But heavy punishment seems inappropriate and it's a good issue to bring up at an in-service training day.
Finally, on the head's alleged bullying style, you must discourage teachers from complaining to individual governors instead of using internal structures, teacher-representatives or grievance procedures. Governors can't help except corporately and within a structure. Real evidence of bullying might justify your chair having a warning word.
As for appointments, are you exercising the responsibility governing bodies have in law over appointments? It is unwise to delegate the whole process. Light involvement in interviews, and attention to advertisements or job descriptions to ensure equal access, can be valuable.