The I-Spy books I were given in the seventies were from the fifties!
I had I-Spy wildlife, flowers and birds, all of which held little connection to what I could spy on the moors around Ossy, so I could never send off to say I'd completed it.
I also had an I-Spy annual from the fifties which was just surreal. It had a photo story about two children in some white caves in France , which I found really scarey. It also had a play in, which I produced (and starred in) at Moor End Primary in 1975, which was very good.