Taking a lead from the Countryside Code, would be workable? Do we need something like this?

The Monuments Code: Respect, Protect and Appreciate
The responsibility to respect and protect monuments lies with everyone, the
public and those that own and manage monuments.

The Monuments Code for Visitors
Leave monuments as you find them.
Take your litter home.
Act with respect towards the feelings and enjoyment of other visitors
Report any hazard or damage.

The Monuments Code for Owners and Managers
Know your responsibilities and liabilities.
Make it easy for visitors to act responsibly.
Identify potential threats to visitor safety and monument conservation.
Adopt transparency when dealing with the public.

Any suggestions welcome.