I'm not sure if these images and descriptions from the 'net, pertain to the question? (if not I apologize)
Is this sign from the same Company? If so, wouldn't this sign be earlier? (I ask because of the "Maple Leaf" logo on Colin's image)
"ANGLO Exploration Company/Purity 99 Gas station sign. Eventually Anglo stations became B/A stations, which eventually became Gulf stations"
"Purity 99 was purchased along with Shawnigan Chemical Limited, Red Head, Anglo-Canadian, and Royalite Oil Company in 1963. In 1968 all stations were changed to Gulf Oil."