Jenni - yes that's it - the little triangle sewn in under the arms. The Australian size 8 is 58cm long in front, 63cm in the back. I've only worn it, and seen it worn tucked.
The Cat - polyester isn't great for me either, but this is strictly in office wear and therefore in aircon. Not what I usually wear in an Australian summer!
Bijou - I got it on special too ($35)
Suz - stricly speaking, two people had them (in different colours) before me - so I was copying them!
Thanks to everyone who has commented!