Just a quick idea..
Did you definitely fit the cross-bar (which has two thick tabs and two narrow tabs) correctly in the actuator i.e. with the thick tabs placed in the thick apertures on the actuator?
It is possible to squeeze the bar into the actuator opening the wrong way round, and I'm just wondering if you'd done this it may not be locating correctly in the exterior handle back-plate (which may not be as forgiving as the actuator).
If it's this, then that's a real easy fix (hope it is
).
Cheers,
Karl.