Master Cylinder Replacing

AAAARRRRGGGHHHH!!!
I've been trying all day to replace the clutch master cylinder in my freelander. The problem is that I can't split the coupling (metalic green). My Haynes manual and a thread on this forum said they just prise apart but that doesn't seem to be working for me. Is there a technique that I'm missing here!!!
In all this snow I loved my car, right now I hate the bloody thing.

Someone please help!!!!

What model is this?? I replaced mine last month 2.0 xDi and it's an unserviceable master and slave cylinder in a combined unit...... Take the clip off the pedal and rotate the Master Cylinder to remove, then **** around to get all the pipework in place.