...even though, as always, your post is thoughtful enough not to sound judgmental.

But yes, there are Ifs and stuff. Most of them have been mentioned by now.
Just this: I know a girl whose fantasy it was to be woken by actual sex, not foreplay. By definition that could never actually be consensual in the beginning (because she is asleep). It would also most likely happen with a person she spent the night with in the first place and that person could probably assume she was up for it again in the morning. Or maybe not, and a short "Stop it!" would already end the whole affair. I hope you can see the two points I am getting at: People are into the weirdest stuff and it's hard to judge such situations from the outside. That's the judges job, not mine, thankfully.
I am not saying this couldn't possibly have been rape, like this politician. Maybe it was. Or maybe her story isn't the whole truth. From what I gathered she seemed very fond of Assange the night before. In the end there are only two people who know if this was rape or not. I would not dare to cast stones at either one of them from over here.