FindMyPast has free access this weekend, but not sure if the 1921 census included.
He is in a Scattered Home in Louth in 1921. "Both parents alive" according to the record.
Thank you for getting back to me, The 1921 isn't free unfortunately, We know he was born to a single mother at the time as she was in the work house and we cant find any record of a father for him, could you advise what record you looked at to find the service numbers so i can try and pin it down as i have had issues finding him on the 1939 register as well.
many thanks