Hi Avrilw
Not too sure whether there is any connection:
1841 Census: Jane Owen age 88 born about 1753, Towyn Merionethshire, Susan*ah Owen age 64 born about 1777.
1851 Census: Susannah Owen, born in Llandovery Carmarthenshire is living in Rhymney Monmouthshire
she appears as a mother in law. Living with daughter Mary, married to David Jenkins.
Not sure if I have helped at all, or confused you more, but Susannah is in my family tree. No trace of John Owen though.
Regards
Jean