Have them seen them often in Underhill - 5 is the record for our garden. The "African Queen! story is, I think, a dead granny but has a pleasing symmetry given that the author of the book on which the film was based lived in Underhill Road....also believed to be an urban myth is the theory they are all descended from a pair Jimi Hendrix kept. I am sure I saw a turtle in the Japanese garden pond in Peckham Rye park last week....I know there used to be several in Dulwich Park lake The Trees of Peckham Rye Park,.....number 1, The Larch....