Now trying to get the heater in. Its the right one from John at justsuds and so is the plastic piece that ducts the air to the screen but I just cannot get it in to place.

Heater goes in fine without it, but when the piece is in place above it I cannot get it in. Any thoughts please ?
The duct is hard up against the dash and locked in correctly on to the heater. The angle changes a bit depending which way you put the duct in but neither allow it much better than can be seen above. Hope that makes sense.
Had the dash out to ensure its not catching that end and the wipers linkage has been taken out as well.