Hi
Only one marriage appearence found on Susan in 1864 as a witness to her own brother in 1864.
Its this lack of information after 1881 that's the problem here and only one name to follow up on that of Plutton, whether its the right one or otherwise wrongly entered I'm at a loss to understand what the likely reasons are for this dead end.
It is possible that emmigration place a part in this mystery.