Yeah sadly seized. I didn't actually put a huge amount of effort into removing it, but my original design involved sawing the stem off to remove the fork. At least this way I could one day liberate it.
I keep looking at them on ebay. Just to relive my youth. I used to have one. I know how rubbish they are. You should free it even if its just to hang on the wall.
Oh no don't sacrifice the flexstem!
(Or is it seized...? )