Siobhan,
I can’t find any birth of Hugh Boyd born 12.11.1918 in Ahoghill or anywhere in Northern Ireland. The nearest was one born on 14.11.1918. And that birth is a bit unusual. He was born Hugh Elliott. He was illegitimate and born in Belfast Workhouse. His mother was Mary Elliott of 18 Lapper St, Belfast. 64 years later there is a note added to this birth registration stating: “Surname recorded as Boyd by me D. Stephen Assistant Registrar General 28.4.1982.” No doubt there's an interesting story behind that but is it your ancestor or someone else?
Your Hugh must have married, so what does his marriage certificate say about his father and father’s occupation? Was Hugh in England in 1939? If so, have you found him in the 1939 register? What information does that give about him and who he was living with?
Boyd is a very common surname in Ireland and we’ll need a bit more information about Hugh to be sure of tracing his family.