I can say without doubt that a right hand blind spot check is required for the 5 times a candidate is asked to pull over on the left (7 times on the PCV test)
Usually a candidate will be asked to pull over in locations where there is a possibility of something happening beyond the mirror view i.e. driveways opposite.
Where there is a fixed number of occasions on the test, in this case 5, many examiners will use the 50% guideline to assess the seriousness of the problem meaning that 2 misses will attract a driving fault each but the 3rd may make it serious as an habitual fault.
The fault location will be in the Move off Safely box at the top of the middle section on the test report.
As for complaining candidates can write to customer services but there is no appeal against an examiners assessment of a fault only if the test was not conducted as per the rules printed in the DT1 examiners guidance