Alfred's Basic Piano Library Lesson Book Complete, Bk 1 : For the Later Beginner by Willard A. Palmer, Amanda Vick Lethco and Morton Manus (1983, Trade Paperback)
This book doesn't proceed too fast, and works largely in 5 finger hand positions. Nice artwork. Its American, and not surprisingly the song titles/themes reflect that culture which can mean that UK kids are a bit unmoved. But I've found that adults over 60 are also happy to work with it: some adult tutors proceed too fast sometimes.