Stuck Headrest

[moo]

Hi all, anyone got any tips on how to remove a stuck headrest?. I was going to try swapping the rears for the front ones, but unfortunately the drivers side one doesn't want to be removed, it's stuck at the lowest position and doesn't want to move at all. I know there's a button under one side of the headrest but this doesn't seem to do anything. I've tried levering it with a large screwdriver as a pry bar, but I don't want to go too mad and damage the seat or headrest.

Any tips appreciated apart from get a disc cutter to it