GMH were a lot slower in recognising trademark infringements than Ford. Ford had a global licensing outlook while Holden were locally based. They hardly looked at the marketing aspect until the late 80's early 90's. They then followed the US style of issuing legal requests to stop and desist using their registered names or logos. At one stage I had a list of both of GMH & Ford for their registrations, which was very comprehensive. This was due to the discussions and agreements about the Restoration Parts Program with Rare Spares over many years. It took a long time for anyone at GMH to make a decision until Mark Reuss as Managing Director took action and completed it within a year.
It may be worth writing to someone like Repco or Autobarn that could have a library of their old catalogues, even older established parts accessory shops may have retained brochures. They may have been advertised in some of the auto books that have been around since that time. Sometimes perseverance is required to track down information.