The 17th Century wooden panel is back home in Flamstead after being stolen three decades ago.
Items found for sale online had originally been stolen from a Hertfordshire and a Norfolk church.
The injunction stops "any unauthorised works or use" at a site built without planning permission.
A council took legal action, but people living in a field say their human rights were not considered.
A High Court judge hears a request from families on the site for "retrospective planning permission".
Questions arise around the issue after a number of caravans settled in a field near a village.
A "number of allegations" are made about an "unauthorised encampment" of caravans in an AONB.
Caravans move onto a field in a beauty spot after diggers spend the bank holiday clearing the land.
Diggers and bulldozers are being used at hillside field in the Chilterns AONB.
