This is a large industrial project dispute, but the practical lesson applies to much smaller projects too. A business contracts with one company, but the work is actually done by people connected with a related overseas entity. Years later, when the project fails and litigation starts, the party being sued says the key documents belong to someone else.
The Court looked at the real working arrangements. Siemens had relied on a related company and that company's employees to perform work connected with the Australian project. Some documents were created by those people in the course of work that Siemens had been contracted to perform. The Court accepted that those documents were within Siemens's control for discovery purposes, either because of agency relationships or because Siemens had contractual inspection rights.
The discovery history also mattered. Siemens had produced documents in tranches after repeated pressure from South32, including an important framework agreement produced late. The Court was critical of that piecemeal process and ordered not only further discovery, but also a director affidavit explaining the searches undertaken, unavailable email accounts, search terms, repositories and document-management issues.
For business owners, the point is not just litigation procedure. It is contract and project hygiene. If you use group entities, contractors, overseas specialists, shared staff or white-label delivery partners, the document trail needs to be under control before anything goes wrong. The contract should preserve access to manuals, source files, reports, test results, emails and handover records. Otherwise, a later dispute can become a fight about who controls the evidence before anyone even reaches the merits.