In order to enter the data and register a pass on the VTS device (MOT computer) the NT (nominated tester) would need to be logged on the VTS device as doing an MOT test ,and enter the brake test results (which must be within the range/tolerance to pass) ,visual inspection of brake thickness during the MOT should have been noted on the sheet if below minimum tolerance, along with any other "faults" found .
when logged on to the VTS device ,during a test , the NT is not allowed to do repairs or adjustments ,just follow the test procedure . any faults MUST be entered on the VTS device , and if that results in an MOT fail ,it MUST be recorded as such .
any required work can then be done (with the presenter's permission)
then the NT should log on to the VTS device , do a partial retest ,and enter the results on the device ,and issue either a pass or another fail . I say that because , in the case where brake or suspension components etc are changed , a new brake test should be done .
In this case ,the garage will say "we tested the car first thing ,the car passed first test, there was some confusion ,mix up ,miscommunication and brake pads and a bulb got fitted by mistake later"
If they don't use that defence then they admit deliberate disregard for test procedure ,which would leave them open to sanctions from DVSA .
"spotty youth fall guy" will get the blame , it's up to the SCC "judge" to decide IF a part refund is "appropriate"
as a matter of principle , "unauthorised work being done" I agree with James 100%
the time and cost and hassle of bringing a SCC claim ,not so much
DVSA could/should be notified of the "deviation from test procedure" but if the garage / test station has history ,they will also have excuses and lies in place as to what went wrong ,probably already have sanctions in place.
(sanctions = it's like a points system ,similar to a driving licence )
Best of luck