Thanks for all your comments, they are extremely encouraging.
Here is an update on progress with the model.
I've been able to add the Cargo door operating handle to the model. The rest of the mechanism will follow.

Also I've now incorporated the door locks. Some of the stringers have also been added to the interior.


Through some XML Kung Foo the cargo doors will;
Open and close automatically with the default SHIFT+E then 2, this also opens and closes the locks.
Open manually by clicking the right side of the plate behind the handle, the doors will only open manually if all the locks have been opened
manually with a right click.
Close manually by clicking the left side of the plate, the locks then have to be manually closed with a left click.
If the locks are clicked either left or right with the doors opening or closing manually the locks will not close.
The doors can only be opened or closed with the aircraft on the ground and only if both props are not turning.
I have also cleaned up the seat cushions and given them a more rounded authentic appearance.

The seats have now been animated. In the case of the Co Pilots seat it can;
Travel forwards / backwards. This will move the view point forwards / backwards. It will only travel backwards if the floor hatch is closed
exactly as in the aircraft.
Raise and lower. This will raise / lower the view point.
Raise and lower the arm rests.

Once again many thanks for your comments, and I'll keep you posted as the model developes.