Tamlin,
I'm not sure where this form originated, it does get completely red in full sun. To my eye, it looks quite different to other red forms, such as that shown in 'The Savage Garden'.
I obtained my seed about 3 1/2 years ago from a nursery in the UK, called Cambrian Carnivores (now unfortunately no longer trading), so it might be difficult to track down it's origins. You are welcome to a big batch of seeds soon, if you want them, which you can share with interested growers on your side of the 'pond'.
Vic