RootsChat.Com

Solved.
Edward Griffith (senior) Married Ann Colpoys. Ann was the sister of the famous Admiral For John Colpoys.
Their son was Edward Griffith junior, who became an Royal Navy admiral. He changed his name to Edward Griffith Colpoys later in life. He had served with his uncle, and his uncle was childless, It may have been to inherit his fortune, by agreement.
Susan was Edward Griffith junior's sister.
She married George Heaslop in the 1790s, and their son was John Colpoys Heaslop.
John joined the navy in 1805 at around 12 years of age,  and served with his uncle Admiral Edward Griffith Colpoys throughput his career. His history is easily googled.  John Colpoys Heaslop rose to the rank of commander, at least, maybe higher. Colpoys is a very rare name in Ireland, in the 1840s there was only 12 households on the census with this surname, 80% in Clare and Tipperary. The Naval link proves the family connection - Uncle and Nephew.

I know the history of this family, right back to Henry Singleton .... several generations further back. Her grandad was John Colpoys, Her uncle Sir John Colpoys, and her great great Grandad Henry Singleton of Drogheda. Edward Griffin took his Irish Uncles name when he died out of respect. But Captain Griffin used 'Griffin' all his like until then. ...I didn't;t know Admiral. Griffin had a sister Susan ?