[Closed] Servicing a Specialized Command Post

I've a 2014 Command Post in need of a service, I've seen the youtube videos explaining how to disassemble, however the head of the post appears to be seized in place - a strap wrench won't shift it and I've tried wrapping the head of the post in an old inner tube and putting it in a vice, but I can't get the head to shift.

Copious amounts of swearing haven't been much use either, despite the many oaths of "bastard!" that I've flung in the post's general direction.

Has anyone else had this issue, if so, how did you manage to disassemble the post?