If someone else in my family has a criminal record would it affect me getting a shotgun certificate at all?

My grandad apparently has a conviction for fighting many years ago when he was a bouncer. Quite a few times, I think he has a criminal record for violence, however, at the age of 68, he is now placid, and hasn't been arrested in years. Would the police take this up as a point, and not allow me to get a shotgun certificate.