Yep, looks like cardiocrinum giganteum to me as well.
Takes seven years or so to flower from a seed, then the main stem dies, and you get offshoots at the base that may flower in about three years. You can lift them and move them at that time, and sashay them into a great space in your garden (dappled shade).
These are not common, so if you manage to get them into your garden ,you will have at least one plant of note to cause admiration in your neighbours.
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All the best.
Peter
