I mean, what? I would have thought there were loads of collector's editons available, or 3-volume sets or something, but I can't see any on Amazon. Various Ebayers are selling whole sets of paperbacks but I want something special...
I love the Famous Five - they were one of the key cultural touchstones of my childhood. I had books and tapes, now all sadly gone, until I saw one in Tesco for a silly small price and started reading Five to Smuggler's Top again. It's wonderful.
If you prefer Secret Seven, GTFO.