Looks like this has turned into a hot topic as more details have evolved. To my mind, this all seems to be a bit of an academic side-show, given how long ago these events were.

What should probably be of concern is that Assange is talking about leaving the Ecuadorean embassy in the UK AND the UK police have taken a much lower key approach recently, removing officers from outside etc.

Has Assange not considered the risk that, given how friendly the UK was to these flights [landing, refueling at Glasgow Airport for example], the flight is probably sitting waiting at Heathrow right now?

If he steps out, he's more likely to be confronted by US agents, possibly posing as UK police, who will detain him and whisk him off to the waiting plane ? The convenient absence of real UK officers will allow for a daylight snatch by the US and bypass the Sweden issue completely.