We started reading these around the age of 6 or 7 , they started off as pre readers with bright yellow borders on the books.
This is the series that, judging from the website, most people remember. Again it had the simple strategy of using colours with the main characters, but as the books progressed complex stories built up preparing the reader for real books. The stories contained elements of magic and folklore and Benjamin the Blue Pirate had the good looks of matinee idol.
Like most of the series these came with their own workbooks, audio plays and as I recall A3 posters that could be pinned on the classroom wall to enhance the audioplays! One of the most exciting parts of these books for me ( no it wasn’t Benjamin’s ponytail ) was The Griffin , The Sea Horses and Merpeople. Exciting characters that I think may have shaped my reading habits for years to come.