I would recommend you borrow a copy of the Haynes manual for the car from your local library.
To remove a headlight unit you need to remove (among other things), the radiator grill and front bumper. The radiator grill is held in place by three clips on top of the grill (approx 100mm from the grill front). To remove the bumper, you need to remove the screws retaining the wheel arch liners and then the bumper mounting nuts (located behind the bumper). The Haynes manual claims the two headlights are fitted (new) as a single unit and that the black plastic running across the vehicle must be cut and a connecting kit obtained from a Ford dealer to attach the new unit.
With reference to the photos within the manual, it is tricky to work out exactly where things are. I would not attempt a replacement without such detailed instruction, otherwise you are likely to have a car in bits, and no way of fitting the replacement headlamp.
Perhaps that explains why your Ford garage wants over �200 for the job.