My first Blyton for older children

The very first Enid Blyton book for older children I read was the ragamuffin mystery. I had run out of faraway tree, wishing chair and brer rabbit books by Blyton (for younger children). But I didn't really understand the ragamuffin mystery and kept taking long breaks from it. But I did eventually read it. I had no idea it was the last one in a series of six books.