All councils were required by the 2000 CRoW act to have Local Access Forum. Though the names have been changed in some cases, I tried to find the LAF meeting minutes some years ago and they seemed to have ceased, shortly after I was dropped from the Shropshire LAF. It took a bit time to discover that the name had been changed to some sort of Great Outdoors Liaison Group and a new record of minutes were on line.
Our LAF had a public question time set into the agenda, some other LAFs have a public correspondence section in their agendas, you may not get far just send a specific footpath complaint in but if you phrase it as a general query about policy quoting facts it should be discussed and you should receive a reply based on the discussion.
I spent 5years on the Shropshire LAF, normal term is 2 years and re-selection, I found myself 'OFF toute suite', as soon as a hereditary landowner took the chair. But over those 5 years I was disappointed how little comment about the access network came from the users of it.
LAFs are supposed to advise the main body of council on matters related to local access so this is the political route into the decision making chamber and also where the bureaucracy, who administer it have to justify their performance in open meeting.