My DS has my surname (not his fathers) and I am about to change my name and he would like to have the same as me. His father wrote a letter saying via his solicitor saying he was walking away from his son not long after he was born - 9 years ago. He doesn't pay maintenance, see him, or send cards. I don't know where he is. The last contact I had was four years ago was when a psychiatric hospital rang me and he was detained there. I know he's not there any more.
There are online deed poll companies that say I need to write a letter saying I don't know where he is, and they will issue a deed poll. But will this be accepted by passport office? If not, are there any other options?