Free Traffic Legal Advice

Hi, hoping for some advice on a TRO related matter. I recently submitted a FOI request to request the TRO for School Keep Clear zig-zag markings on a road and whether it went through a consultation process. I got a reply back stating that the Council use map based TROs, along with a screenshot of the restriction in question. I was under the impression that a TRO is a legal document, so was expecting something a bit more official like a document. Am I wrong here - are map based TROs perfectly valid? Thanks