The police were arresting him for skipping bail - that's not a political asylum issue.

No, but politically persecuting Assange under pretexts is. Since (I assume) Ecuador protected him not because they oppose persecution for sexual assault, but because they believed that was a pretext for political persecution, I do not see how the circumstances have changed. Except for the Ecuadorian embassy staff reportedly getting fed up with Assange, of course.

One of the ways that things have changed is the continued illegal political campaigning whilst in the embassy that Assange is accused of. Asylum doesn't give protection against breaking the law in the host country.

The police were arresting him to extradite him to the US.

https://www.theguardian.com/media/live/2019/apr/11/wikileaks...

> Scotland Yard has confirmed that Assange was arrested on behalf of the US after receiving a request for his extradition.

That was a further arrest, after he was in custody. This is relatively common in the UK.

They may have assurances from the US that they won't extradite for all we know.

Or that US prosecutors won't seek an extended jail term or death penalty. Not that those were likely on the table anyway.