I'll tell you what I know about Jake Buxton; and how I know it.
In the summer of 2013 Buxton lined up a move to Birmingham City; Lee Clarke, the Brum manager had even offered him the club captaincy. Derby County blocked the move, saying that Buxton could leave, but they wouldn't let him sign for anyone they considered a promotion rival.
Nigel Clough became SUFC manager and spent the next two seasons pretty much constantly trying to get Buxton to sign for the Blades. However, Buxton wasn't having any of it, because at 28/29 years old, in the prime of his career he wouldn't take the step down to league 1.
I know this because the parents of someone I know run a pub in Sutton-in-Ashfield which happens to be Jake Buxton's local, and the lad I know regularly speaks with Buxton in the pub.
I was told this info about a year ago, and I haven't got any more recent gossip.