Seat posts... urgghhh, don't remind me. The last time I tried to to remove one I had to cut it down and s-l-o-w-l-y hacksaw the inside of the tube. It was awaste of time, the "post" was a random piece of aluminium tubing about three sizes too big and 2 feet too long. How the idiot ever got it so far down the tube I'll never know. The bike, despite being otherwise decent condition is currently residing in a pile of scrap metal at the recycling centre.