I was surprised I got this job done in 1.5 hours , the pic shows the cut away plastic with the motor removed , it really does take 2 minutes if you have a multi purpose saw ( Fein saw ) but you could do it with a chisle .The door card really does pull off quite easily once the 3 screws are undone, just give it a hard yank .
Re the door handle . Remember to take off the steel wire door pull that goes to the handle as there isn't one on the new lock you have to change it over . To release that you have to keep turning the lock screw on the end of the door until the small cover wiggles out, you can then see the end of the wire located in the handle, you just lever that out carefully and extract the old lock.
The 2 bolts holding the lock are Spline grooved I had to borrow one of these wrench tips. To get the new lock in you have to take off the door plunger tip/ knob, to do this you move the mech towards the back of the door and it will then pull out , once that is done you can take out the old lock and remove the wire from it's locating hole.