The handbrake should self adjust with the wear of the brake pads/discs, this means you can adjust them to a degree without adjusting the cable.
If you jack the rear of the car up, only needs to be slightly off the group. And pump the hand brake a few times, until you feel it is enough. Not sure how much this can be taken in by though so it might be worth doing the correct way.
Iirc for the MOT the handbrake needs to be 100% between the 4th and 7th click (im sure i read this in the Haynes manual)