It’s the job of qualified teachers to do learning walks and observations and to look at what’s working and what isn’t. It’s your job to accept their assessments. And no, that doesn’t mean you are simply accepting what the head is telling you, because it’s not the just head that’s telling you it. It’s professional teachers, and the default shouldn’t be not to trust them.
At no point would I as a governor carry out a learning walk or an observation. I might accompany the HT or SLT as they do a learning walk, in order to see for myself the things I’ve been shown on paper are being done in the classroom and not to burden the teachers with a succession of visitors calling into their classrooms.
You don’t usually get the teachers coming to governing body meetings (though I’m sure they’d be thrilled to spend another hour or two in the school of an evening), so we cannot just accept what the HT tells us. That isn’t holding someone to account.
That’s why you go into the school, on a pre arranged and agreed basis, so that the professional teachers can show you what they are doing. And sometimes they tell you that actually what the HT has waxed lyrical about just isn’t working, or they can demonstrate why some groups are doing better than others and why (context is key and not always transmitted by sheets of data).
Seeing the lifeblood of a school- the pupils and the teachers - also enables you to connect with and champion the school, which is a damn sight better than sitting in the ivory tower with the SLT looking at data but having no clue about the pressures the teachers are under, or never seeing a lesson and appreciating what’s actually being done, what’s possible and what’s not.
But governors should never judge teaching or provide feedback on teaching. It should always be linked to looking for examples of what the HT / SLT has told you they are doing to improve outcomes. And if sometimes you get roped into listening to someone read, or can ask a pupil what they like about school, or hear them tell you that they used to find maths hard but they are enjoying it more since they got extra help or whatever then that’s just an awesome added bonus.