The Mr. Men by Roger Hargreaves. In the early 1970s they were made into simple animations. The narration was by the marvellous Arthur Lowe, most famous for playing Captain Mainwaring in Dad's Army. He also appeared in Coronation Street as Leonard Swindley who was jilted at the altar by Emily Nugent (now Bishop).
In 1970 Lowe narrated a story on Jackanory, The Emperor's Oblong Pancake by Peter Hughes, otherwise prior to the Mr Men there doesn't appear to be any other narration work.
If you ever hear me telling a story I often have Arthur Lowe in my head!
Well here's my favourite, Mr Topsy-Turvy