It used to be the case that with the hand written forms that you tested the car and then filled out either a pass or fail sheet.If the car failed on just a bulb,what should have happened was you filled out a failure sheet,replaced the bulb,then filled out a pass certificate.In the real world most testers would test the car,replace the bulb,then fill out a pass certificate.This obviously gave a false impression that the car had passed the test with no work and this effected the average pass/fail rates for both individual garages and nationally.
What happens now is that you register the car on the computer system,this then prints a check sheet.You test the car,and then you can do one of two things.If it has failed on a number of items,then you go to the computer and log the faults and print a fail sheet.If the car fails on anything that takes no longer than around an hour(i.e minor faults like bulbs,blades,tyres etc) you can repair the car and then log the items under PRS.This allows you to log the failure items,but it prints off both a pass and a failure sheet.This shows that the car has failed,been immediately repaired,then passed.
The only thing that you can do other than the proper test procedures during an MOT is adjust the headlight aim if it is out.Apart from that you should carry out the whole test and then decide whether to repair the minor items or fail the car.
When the MOT computerisation system first came out it was universally disliked by all garages,but as we got used to it,it has been a definate success.It takes a lot of the time consuming writing of certificates and log forms,and gives VOSA an instant idea as to the standard of MOT testing in individual garages.They now know how long a test has taken,what the vehicle has failed on and many other things as soon as the details are logged on the computer at each garage.
I hope that makes sense.