Recently a neighbour of my parents started construction work on a block adjacent to their house. My parents live in 'The Hills' in WA which if you are not familiar with this area it means that to build on these blocks it requires extensive earthworks and retaining walls. The neighbours have, without asking any permission or having given any previous notice, put wooden struts through my parents stone retaining wall. This wall is valued at approximately $250K if it had to be replaced. My mother has complained formally to the council & they're investigating but can anyone advise me of their legal rights? As the wall is a structural wall it is very important that it is not compromised in anyway & they have punched many holes, at least 12, into this extremely important part of their property.