Alastair:

UC Davis actually has this tree in their collection. I took their collector out there about 10 years ago. I wonder if they've evaluated it.

I sent it to someone several years ago in Washington DC and it fruits, so it's common. And for years, I have have discussed with a fellow fruit enthusiast who also knows this tree (and gave it its name) whether it's a seedling or planted/known. We believe it's a seedling, based on the location and the unique appearance of the fruit.

It's in a very public place. I know that others have picked the fruit for years. Hard to name one person who found it. The name came from my friend, who is growing the tree in many small pots to eventually plant or sell. He has known about the tree for many years also.