You are worrying about nothing. This is the MOT manual, verbatim:
6. When the brake is fully applied:
a. knock the top and each side of the lever and check that the lever stays in the on position
b. check that the lever is not at the end of its working travel and that there is no fouling of adjacent parts
c. check that the lever is not impeded in its travel.
At 8 clicks (just), the lever is nowhere near the end of its travel. The recommended adjustment is 7 to 10 clicks, so your's is well within spec.
The mechanic, in his infinite wisdom, thinks 8 clicks is near the end of its travel. That is his opinion. In his opinion it is not unsafe or he would have failed the car. My handbrake, in 14 months, has never budged from where it was so why should yours (unless you are into drifting and handbrake turns). Don't worry about it. Enjoy your car for what it is