Information accessible to applicant by other means
You go to great pains to emphasise how harmless the information was by saying that it was very widely available. In doing so you have undermined your point that your request should have been processed. That in itself is an exception under s 21 of the Freedom of Information Act.
Sub-section (1) states that: "Information which is reasonably accessible to the applicant otherwise than under section 1 is exempt information."
This exemption exists to promote efficiency, as there is no need to provide information under an FOI if it is already freely available. Indeed to do so would waste time and resources.