Sliding cabin door latch removal

[simonfraser]

I have one of these:

http://www.ebay.co.uk/itm/Southco-M...Cabin-Door-Latch-Aluminum-5-5-8-/172087410845

Key will not rotate all the way to lock the door

I have removed the locking pin to slide it out of the door, but its still stuck, any ideas what i need to do to remove it ?
Have gently tapped it, no movement, looks like i am missing another fixing

 

[Portofino]

Is it all lined up on the door so the two jaws clamp the post evenly ?
Post needs to be in I think to remove in locked mode

 

[simonfraser]

Door section below the latch appears a loose fit.

It's somehow caught in the upper groove, cant see a screw or fixing.
Gave it some more welly last night, but the door is plastic ....

Just split the lock with a big screwdriver, it should have slid out.