gearbox/engine split

Guys am desperate for an idea here so any suggestions are more than welcome.
I am in the process of removing a 1.8 petrol engine out of my freelander and am now in the position where I am trying to split the engine from the box.
I am removing the engine leaving the box in situ which I am advised that I can do, however i am struggling to split the box from the engine despite there being sufficient room to slide it from the gearbox drive i cannot in any way split the two. I have got as far as creating a 1/4" gap all around the gearbox/engine join.
I have disconnected the clutch cable and let the lever on the box relax back in its position.
Does anyone have a good idea of how i can remove the box totally from the engine (I think that it is the gearbox drive which is preventing the full removal). I have tried crow bars between both but am afraid to use too much force in case I damage the gearbox casing. I am not worried about damaging the engine as I have a replacement.
(I am changing the engine due to damage following cylinder head going but the car is new to me and I do not know exactly what happened to the engine, upon turning the engine from the crank it sounded like the damage was bottom end if that helps)
Helpppppppppppp
Thanks John

Think that I may have the answer myself.
I think that I have left the plate that holds the driveshaft which is bolted to the engine connected.
I will check this out when it is light and has stopped snowing.
Bloody idiot should be my log in name