Where Can I Get A Greengage Fruit Tree, And How Do I Grow Them?

Question I recently visited France and was lucky enough to eat a Greengage, it tasted amazing. I already grow one and I think it is a ‘Doree’ cultivar. Can you suggest where I might buy the cultivar ‘Reine Claude de Bavay’, also known in Australia as ‘old greengage’? It was a wonderful fruit, I ate…