The father of Emma and Sean left the family when Sean was three and Emma was five, which makes Emma is two years older than Sean. In Series 5 Episode 2, Ash mentioned to Mickey that Emma had been out street at the age of 14 and Sean, nine. Emma was initially five years older than Sean.
It is extremely unlikely that a three year old Sean vowed to kill, or at least beat up, his father, and recognised him twenty or more years later.
It is extremely unlikely that a three year old Sean vowed to kill, or at least beat up, his father, and recognised him twenty or more years later.