Hi Alastair,
On website www.eggsa.org, there is a photo of her gravestone in Plettenberg Bay, Marine drive cemetery as:
RAYNER, Ella Edwards
29.10.1916 - 15.07.1997
"A wonderful woman of great strength, kindness and humour. Remembered with love and admiration"
Also, in Ancestry24, there are two Government Gazettes:
GOVERNMENT GAZETTE No. 18681 – 20 Feb 1998
Section: Notice to Creditors in Deceased Estates
Record Type: Legal Records
2485/97 - Rayner, Ella Edwards, 1916-10-29, 1610290019004, Flat 40A, Park Drive Retirement Village, Park Drive, Port Elizabeth, 6001, 1997-07-15. B. S. Rayner, 110 River Road, Walmer, Port Elizabeth, 6070. 30 days.
GOVERNMENT GAZETTE No. 18976 – 19 June 1998
Section: Liquidation and Distribution Accounts in Deceased Estates Lying for Inspection
Record Type: Legal Records
2485197�Rayner, Ella Edwards, 1610290019004, Flat 40A, Park Drive Retirement Village, Park Drive, Port Elizabeth, First and Final, 21 days (Port Elizabeth). - M. J. Rudman, c/o Coopers & Lybrand, P.O. Box 27013, Greenacres, 6057.
Hope that helps,
Kind regards