Suggestion:
Work WITH the school, not against them. Believe it or not, teachers do have your child's best interests at heart and having confrontations with parents does not help. We want to work WITH you, for the sake of your children.
Take it from me, Ofsted WILL NOT be interested in a complaint about reading books. However, they do rate good partnership models with parents, such as a Parent Forum, where issues like reading books and homework can be raised and discussed with the HT and a named governor, on a level playing field, observing agreed ground rules. HTs and teachers acknowledge that these issues are important to parents - the majority of us are parents ourselves.
If your child's school does not have a Parent Forum (or similar) make an appointment with the HT and discuss the possibility of one starting up. It's a win-win situation - parents get to have their say, the HT gets to know what parents think and the school gets Brownie points from Ofsted. Much better than gate gossip any day.
Any HT worth their salt will listen to parents and act where possible and reasonable. I recently committed a large amount of money to improving the entrance at my school - an issue which was raised at the Parent Forum and about which I would have been totally unaware had it not been raised.