A bit silly.
What he's doing--basically, is pressing the government to prosecute him or not.
The problem is, if the UK decides to drop prosecution he will subject himself to being extradited again; since the original extradition case was only stopped to pursue local prosecution; the extradition was not dismissed on merit.
Of course they've done bit copies of everything. You don't forensically investigate the original media. This would be ridiculous. Anyone experienced in cyber security knows this, and the importance of proper chain-of-custody. Even with the copies, as soon as they return any evidence, CoC is lost; making any copies worthless. This is likely the main reason he wants his property back.
Since it's been in government custody for 5 years--it's hard to say what sort of malicious hardware/software they will put on it. So he isn't going to want to use it. I doubt he's this stupid.
Biting the hand that feeds IT
