I well remember bird feeding was a completely domestic affair in the 50s (bread, bacon rinds, peanuts, coconut) and there was very little plastic around then - it was a time of paper bags, paper cups, paper straws and carrying a string bag for your shopping.
As to when compost in bags became available,I remember Gardeners Question Time going on about John Innes, and they weren’t expecting you to make it up yourself. But the line-up I remember was “Fred Loads, Bill Sowerbutt and Professor Alan Gemell of Keele University” and Keele didn't get its university status until 1962.