You might have found what you are looking for since you
posted almost two years ago.
There are quite a few Hewsons on the Irish genealogy projects web site, including a few from Deansgrange.
go into www.igp-web.com/igparchives
and enter Hewson in search
and you get 55 in totalhttp://search.freefind.com/find.html?pageid=r&id=1381278...
you might see something relevant to your search.