Which way are you trying to remove it?
When I dismantled my L5 to move it (it was the only way available), I removed the leadscrew and feed-shaft completely, chocked the underside of the apron with blocks of wood then separated the apron from the saddle by removing the Allen screws that hold it up.
There also a couple of dowels in there so be sure to lower it and refit it vertically.
Obviously, take the leadscrew especially out carefully and slowly, with as much support as you can give it, so you don't bruise its and the half-nut's threads against each other.