My search for Gertrude Annie Lacey

I have been searching for a few years now for the daughter of my great aunt and her husband, Gertrude Annie and Ebenezer Moses LACEY. I knew from various sources that they had emigrated to South Africa in the early 1920s and that they had both died there in 1940 and 1944 respectively.
On one Gertrude's visits to England, however, she was accompanied by a daughter, also called Gertrude Annie, aged 14. Also on Ebenezer's Estate Papers from South Africa he left some of his money to a Gertrude Annie MOORE, wife of Ronald MOORE. I had worked out her birth year as being around 1915 and so proceeded to look for her birth in England around this time. I knew Gertrude and Ebenezer were married in Camberwell but could find no record there. I searched baptisms in Gertrude's home County, Nottinghamshire and Ebenezer's in Buckinghamshire but still no luck.
Could she have been born in South Africa? I could find no record.
I read Ebenezer's Estate Papers again. Even more puzzling was the fact that he had stated that he had no surviving children. So had Gertrude Annie died at a young age, and if so, where?
This puzzle carried on for a couple of years, with me regularly checking records both here and in South Africa but to no avail. Then last week I had a moment of serendipity.
I had joined a South African genealogy group on Facebook and at the same time Ancestry was running one of it's free weekends for all UK records.
I had posted a request for help in finding information relating to the family and the whereabouts of young Gertrude Annie.
After a few messages concerning Gertrude and Ebenezer and their immigration I started to look through some of the old records I have for them. One came to my attention for an outbound journey that Gertrude had made in 1921. I noticed that a few lines above her entry was another traveller giving the same address in Camberwell. It turned out to be a Gertrude Annie GRAINGER
Who was Gertrude Annie GRAINGER? She was the daughter of  Gertrude's sister, Edith.
Edith ELLIS had married George William GRAINGER in 1910 but unfortunately George was killed in action in 1918. Edith had married again in 1919 to Arthur BOWLING.
I will probably never find out why, but poor little Gertrude, then aged 3, was taken to South Africa to start a new life. Did she ever see her family again? She did come back, we now know, listed as Gertrude's daughter and not her niece, but did she have any contact with her mother?
Helen Riding of the South African genealogy Facebook group found evidence of a marriage between Gertrude Annie Grainger and Charles Frederick Ronald MOORE thus proving the reason for Ebenezer leaving some of his money to Gertrude Annie MOORE and her family.
Later the marriage entry for them was found by Ellen Stanton, also of the group, in the Familysearch records for the Parish Church of St Augustine. Orange Grove, Johannesburg South Africa.
Also mentioned in Ebenezer's will were two children, Mary Gertrude and Edward MOORE. I have managed to find a baptism at the same church for Mary Gertrude in 1943 but have yet to find one for Edward, although we did find that he was born in 1947 from a later ship's register for a journey to England in 1950.Two years later, however, he did not travel with the family when they made another journey.
I am currently trying to find out what happened to the family after 1952, the last journey I have for them travelling back to South Africa.
Thanks to Helen Riding and Ellen Stanton of the South African Genealogy group on Facebook.