I had the very common problem of the traction control triangle and abs light on the dash with no speedometer so found information to try to establish which (if any) of my speed sensors were at fault.
I tried removing the passanger rear sensor to inspect it but it seems that it had perished so badly that when I tried turning it to release it the piece where the bolt goes just fell off and when I attempted to pull the rest out with a mole grips, that just snapped off too. So all that was left was trying to pull it out by the wires which of course snapped.
At the moment it sits flush with the hub and i've made no further attempt to remove it.
I decided to try posting here in hopes of tried and tested methods of removal (hopefully easy ones that won't require dismantling the whole axle)