So, here is what I have found about the Electric Supply Company of Victoria (Wikipedia):
So, maybe the car is part of the State Electricity Commission of Victoria, and as they built quite a bit of electrical infrastructure for brown coal and natural gas in regional Vic during the 70's, I Hopefully i can get a period image of the car (or one like it) from this time.Quote:
The Electric Supply Company of Victoria was a British company with its headquarters in the English city of Liverpool. It was formed in 1903 as a subsidiary of the British Insulated Wire Company. The company operated power stations and electric tramways in the regional cities of Bendigo and Ballarat.[7] The Electric Supply Company of Victoria was acquired by the State Electricity Commission of Victoria in 1934.[3]
Fingers crossed and I can get a reference pic from the Victorian Museum.

