Headlamp aim fail is just to keep VOSA happy.
The test is to check that the beam doesn't fall into prescribed areas and dazzle oncoming traffic. It is NOT a check that you can see where you're going.
So? What I am saying is that the headlamp aim is fine, but it goes down as a fail just so VOSA can see a fail. There is no charge for 'fixing' it and a pass is issued immediately after.
there is no fail quota an mot station has to meet
but if a car is presented for MOT with a headlamp aim out of tolerance, it should be a fail on the system ,so vosa know about it ,
many cars aim is adjusted with a simple turn of a screw (which some MOT garages charge £25 + vat per side to adjust)
say every 2015 ford fester is presented for MOT and the brake light bulbs are blown on most , VOSA would recognize a pastern and investigate .
if the NT just replaces the bulbs while testing ,no one would know that ford festers are crap
just an example
not saying all 2015 festers have blown brake bulbs
headlamp aim and emissions are easy pickings for rip off garages to charge for because not many of us has calibrated headlamp beam alignment testers or emission machines
I've seen people in main dealer service center receptions parting with £500+ for mot repairs on 3 year old cars