I know you're a private school parent, and I accept that you view the VAT issue differently from me.
But you said It is not an unreasonable philosophy that all education should be comprehensive, consistent and state-provided
I disagree that it's "not an unreasonable philosophy". I'm pointing out why I think it's unreasonable, and asking you to explain why you think it isn't. Your 2nd paragraph doesn't address that.
I'm an atheist too. I respect most tenets of most religions - as in I respect that they are a reasonable way for followers to live their lives - but I don't accept all religious tenets or working practices as being reasonable. I consider the treatment of women within some religions unreasonable, for example. If I were to say that a religious tenet or practice is "not an unreasonable philosophy" then I would expect to be able to defend the reasonableness, even if I don't believe or follow the tenets myself.