On this strata titled land, all external areas have been designated as common property (including the individual unit's court yards). Only the buildings themselves have been defined as being owned by the owners. The front unit had an issue with an unapproved patio in their court yard and proactively applied for retrospective planning approval. As all external areas are common property, all four owners of the strata title had to provide their approval that they had no objection to the patio being on common land even though it would only be Unit 1 using their "private" patio accessible from their back sliding door. The council has now advised the front boundary wall (which is also the wall for unit 1's court yard being on common property), and some of the level of the land within the courtyard have not been built according to the original planning application (20 years ago). The boundary wall is on common property. Whose responsibility would it be to pay for and get this wall and raised land approved under Property Law? All the strata owners (as it is on common property) or unit 1 which benefits from the wall and the raised land (is part of unit 1's court yard).