"Sexual offences are an extraditable offence"
Part of the defence was, I believe, that what he was being charged with wasn't a sexual offence in the UK.
And the "Australian national" thing is irrelevant as we are obliged (morally and constitutionally) to not send anyone somewhere to suffer unfairly, regardless of nationality.
Personally, I think he should go and defend himself. If he's innocent, congrats, if not, obeying the law in the country you're visiting and taking personal responsibility is part of life. I've got nothing against the guy, but he sounds like he's just trying to avoid giving his side of the story in a court.
I may be naive, but I don't believe Sweden will be able to get away with an extradition to the USA, even if they wanted to. Any extradition from the UK would not allow a forwarding extradition without concluding the original trial, and we constitutionally can't extradite someone to a country where they face cruel punishment (i.e., death).
I'd be first in line to protest his release should he be couriered out of Sweden.
(Beer, since I'm off tomorrow)