Elusive Adam Irwin

Hoping someone can point me in the right direction! I have Adam Irwin (spelt his name this way 1805 in Battle of Trafalgar lists). He was a Marine, said he was born in Ballymore, Antrim  (I know his presumably Irish accent may be confusing to an English ear!), served on HMS Conqueror in above battle, occupation given as Marine when married and a widower 1815 in Devon, England to Ann Murfy (Murphy) from Belfast. Had 5 children, all born in Plymouth (which was a big naval base). He died in Devon age 67  in 1829 , occupation = pipe maker, address Water Street. His age means he was born 1762 ish, but can't find Ballymore in Antrim. Also looking at the Irish Genealogy site irishgeneaology.ie I find an Adam Irwin in Dublin, 1794 with wife Jane, baptisng son Joseph 16.10.1794 at St Catherines C.O.I. church. I'Im assuming this is the same Adam marrying in Devon as a widower. Not many Adams around in that day!! Is/was Ballymore maybe a small village no longer existing? How can I find out more, including his parish? Struggling to find out more about Adam. Would love to go further back, but would like to understand more about Adam and his life in the 1st place. Was he a pipemaker before a Marine? Was he on a farm? What about his family in Antrim??

Would appreciate any pointers anyone can give me, or suggestions. 

Thanking you hopefully! Lesley Frame