Her birth index:
First name(s) GILLIAN M
Last name BUCKLEY
Birth year 1936
Birth quarter 1
Mother's maiden name Burmester
District Kensington
County London
Country England
Volume 1A
Page 164
Record set England & Wales Births 1837-2006
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There are 24 Gilliam M Butlers who married in the 20 years from 1969 to 1989, so there is little hope of finding any subsequent marriage let alone the surname she might have been using when she died..
But
ThePeerage.com asserts that she married John Osmael Scott-Ellis, 9th lord Howard de Walden in 1978. But I cannot find this marriage on FindMyPast from 1977 to 1979 either under Butler or under Buckley. Might they have married abroad? That cannot be found either, but FMP is weak on worldwide data.
CP, however, in the Howard de Walden article in Vol XIV, p. 392, records the marriage but only the year, not the date or the place.
It would be unlikely that she and her second husband had any children.
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