HTFB has written what I was going to say.
I used a left hand tick for years and ignored any comments from others about it.
My brother, who was a head teacher at the time, wouldn't accept my opinion that a left handed tick was valid, asking me if I used a left handed b, for instance.
Since then I try to use right handed ticks when completing forms by hand.
Other than that I don't care what others think of my left handed tick.