I don't know whether this information will be new to others, but it was new to me, and I do not find it in the archives of this group.
James Henry Ion Villiers-Stuart, of Dromana, died in 2004, according to his gravestone, and his widow in 2021.
Also, the gravestone of James' mother, Elspeth, days she died 10 April 1943, which is slightly different from what I had seen on at least one source.
James Henry Ion Villiers-Stuart
Birth
30 Nov 1928
County Waterford, Ireland
Death
Aug 2004 (aged 75) [the gravestone itself gives only the year]
Villierstown, County Waterford, Ireland
Burial
Villierstown Church Graveyard
Villierstown, County Waterford, Ireland
https://www.findagrave.com/memorial/150157792/james_henry_ion-villiers-stuartEmily Graham Villiers-Stuart
Birth
1930
Death
2021 (aged 90–91)
Burial
Villierstown Church Graveyard
Villierstown, County Waterford, Ireland
https://www.findagrave.com/memorial/268962933/emily-villiers-stuart