just hold the colar in on the elbow and pull the macro line, then get a spanner (its gonna be tough because it has locktight on it) and just twist is ANTI-clockwise, remeber LEFTY LOOSY RIGHTY TIGHTY haha. u dont want to snap anything! if u are still having problem just get a lighter and try and melt as much as the locktight as you can, dont worry it will come off and u wont break anything if u do as i said. just is will be tight so give it some elbow grease!
oh and just read your last post and just get another spanner which fits the velocity adjuster and have on on the elbow joint and one on the velocity adjuster and twist them in OPPOSITE directions.
james