Well... I've spent a couple of hours on this and I'm done.
On its own, I didn't think I'd done too bad, but when I play it alongside the original it sounds a pile of pants.
I'm too embarrassed to put this on my SoundCloud site
http://synkrotron.co.uk/Upper_Hand.mp3 And there's not a cat in hell's chance I'm posting it on the recording review website.