There has to be an explanation!!
It could be that he was born before the marriage of Levi and Ann and never christened or registered 
What does his marriage say about his father
Rosie
Rosie,
I found this listed on the Genuki site, under baptisms:
09 08 1863 01 08 1863 George LUNN Levi Ann Bolton upon Dearne Son Coachman
(The first date is the date of the baptism, the second the date of birth!)
Dave