At the time I knew that it was the Social Centre for General Motors Holden at Fishermens's Bend and I'd been lucky to visit there in 1996 and get a guided tour from the Centre manager. But I didn't know when it had been built.
This week, however, I have been doing some work with the City of Port Melbourne Building Permits Register and was delighted to come across a entry dated 31st January 1945 for a canteen to be built for General Motors Holden by Richmond builder E A Watts.
So now I have my date. The GMH Social Centre was built in 1945.