I assume disassembled front fender means removing the fender liner so he could access all the hardware to remove the headlamps. That was good of them to not charge for labor, but it's unfortunate that they charged for the new stepper motor due to (presumably) their own error previously. That makes for an expensive xenon bulb, and a bit of a headache including the BMW diagnostics. (although that was really your own decision to pay for that.)
Still glad to hear they didn't just turn you away like some shops would do and made time to fix the issue immediately. Not sure how comfortable I am with expensive mistakes on such minor jobs though.
How long have you had condensation in your headlight for before the stepper motor died?