Tattoos and piercings are not a modern day phenomena. Having them doesn't preclude success or failure.
Pre-conceptions of a person for the way they carry themselves/dress/decorate themselves should be consigned to the dustbin.
Well, it's a special needs school that educates those deemed to be unsuitable for mainstream schools and those unable to attend mainstream. Thereby it has an ethos of inclusiveness. Nothing to do with 'left-wing PC nonsense'.
I work in a school and plenty of the staff have visible tattoos. It doesn't appear to affect their ability and it encompasses the ethos of inclusiveness.