If the headlight housing is still OEM then you will have a vertical and a horizontal screw on each headlight to set them at the correct height. Park approximately 1 metre away from a wall/garage door and check the pattern against it. The pattern should be horizontal on the right side of each light and slope upwards on the left hand side of each light. Get into the car and slowly reverse approximately another metre. The horizontal section of each light should drop slightly as you reverse, if it doesn't the headlight is set too high. It is only a rough way of setting the lights, but would ensure you don't fail the MOT.
As they are HID's I don't know for sure if the light spread will still be 100% the same, but you should still be able to ensure that they aren't directed too high.
As for removal - You need someone to post who's had them on
EDIT... The adjuster screws are quite awkwardly placed and you may need a stubby screwdriver to get in there