who did you do training with? If you hold a nail qualification you should have been taught how to infill. i'm afraid you may get a hard time about a question like this (especially with your profile not filled in) . I would suggest retraining with a reputable company, who will provide you with the education you need.
Sadly it seem's to be rushed over and missed out offten !
maybe its because some collages know that the training products arent good enough to last till a re-bal , or maybe they dont want the extra time of another assessment?
I WOULD love to know why,
when I did NVQ we wear toled how to do it ,not shown and we didnt get to try it out ,
like I said I would love to know why it gets so left out .
Don't worry! It isn't a trick question. I hear this all the time!