It's been known for OFSTED inspectors to try to get access to schools without showing ID. I heard one story (may be apocryphal ) of one getting quite angry and demanding access. The admin stood her ground and refused her admission until she showed the card. That school passed. But I did hear of one where the inspector was able to get access by walking in another entrance that wasn't secured. Instant fail ( there were, as it happens, other issues about management that deserved the fail imo anyway).