The MacDonald Junior reference library series was wonderful, every topic you can imagine covered perfectly for the 10 – 12 year old. From Fuel to Fishes!
The Travels In Time series published by Holmes McDougall http://schoolreading70sbooks.weebly.com/history-books.html
Another series for young children that would cover any topic from ghosts to steam engines. http://schoolreading70sbooks.weebly.com/piccolo-explorer-books.html
An illustration from Adventure in the Sky – Dolphin Books 1960 , illustrated by Raymond Briggs and written by Eric Roberts.
A page from the New Step by Step Story Readers Book 1 – Harrap from possibly 1950’s.
A page from Speech House – McDougall’s Educational 1957
Another illustration from the 1970 reading scheme Sound Sense by A. E. Tansley.