I saw one of these last year, it was still in a pot after several years. I couldn't believe how big the flowers were.
Heather

It is a bizarre & exotic looking thing. Some people will tell you you shouldn't be growing anything other than the native vine, but then I've never seen a Richmond Birdwing butterfly within cooee of my place to get poisoned by an exotic. And I've seen one growing some years back and was told by the grower that it never set seeds for him, so had no tendency to be invasive. Anyway it's not got anywhere to escape from your place Ian. Could you favour with a photo that would put the size in perspective?