Here's a link to the Chelsea Pensioners archives: https://www.chelsea-pensioners.co.uk/tracing-ancestors
You might be able to find out more info about your relative.
Good luck with your search.
Message Board Replies
Liberty1959Monday 3rd May 2021, 01:51PM
The free site www.irishgenealogy.ie (Church Tab) has a four-five Timothy Callaghan baptismal records in the 1790s at the Cork South parish (St. Finbar's). Likely these records are too late if he was born around 1786. The other issue is not having the parents names to be able to verify any records you locate.
Castlemore Roscommon, IrelandXO Volunteer ☘Monday 3rd May 2021, 02:28PM