I'm afraid the initial decision may as well be a staged attempt by the UK to save face, so they don't appear to the rest of the world as a spineless lackey of the US. The US is really in no hurry to get their hands on Assange. They'll play along as long as they know that Assange stays in a prison somewhere, till they get a favourable extradition ruling.

If the UK is really serious on the well-being of Assange, they should allow him to seek asylum and relocate elsewhere, without obstructing him as they did in the case of Ecuador.