Charles O'Hagan had son John bon around 1840 and married in Stranraer Scotland in 1862

John's 1862 Scottish marriage marriage certificate should contain both his parents occupations, plus it should say whether they were alive or dead at that date. You should be able to view that certificate on the Scotlandspeople site. If you post the information here (or attach a copy of the certificate) we'll try and help find that family in Ireland.

Further to the above, I can see a marriage between Charles O’Hagan and Mary Keller at St Patricks RC in Belfast on 25.5.1823. I don’t see John’s baptism though. There’s an Edward Hagan baptised at the same church on 31.1.1830 to parents Charles Hagan and Mary Retter (that might be Keller mistranscribed. Looking at the original it’s certainly possibly Keller).  The O’ prefix to Hagan and other Irish surnames was often dispensed with so it could easily be the right family. The RC parish records are on-line free on the National Library site:

https://www.nli.ie/en/family-history-introduction.aspx

Thank you Elwyn. This is very helpful as it takes me back one step further than where I was, very much appreciate your help.

Regards

Douglas