Antony, Thanks for your input.
There are two children in question.
First child born with a certain Surname, in 1950.
The mother then marries in amj 1952 to a person who the second child ( born in the February)relates to and has the fathers surname.
Both of these children are then re-registered in jas 1952, the first child's surname now reads the same as the second child.
This seems to me done to keep both children with the same surname, but how would you be able to have a child and then re-register him 2 years later under another surname ?