From this basic starter we have found her and her husband on the 1911 census and gone backwards and sideways in order to see if there was a story which could be told.
Florence was called 'Teresa' in all censuses up to her marriage. Her parents were Bernard and Mary Ann, and she had three older siblings including one with the rather extraordinary name of 'Adalbert Roderick Maximillian' !
As she was living in a pretty big house with 13 rooms on the 1911 census, I had a look to see if there were any Annegarn's appearing in the newspapers. The only one I found was that of her father, Bernard Joseph Christian Annegarn, who was a "colonial merchant" on the 1861 census living at 13 Ashburnham Terrace, Greenwich. He became bankrupt in 1864. Wealth must presumably have been on the Dawnay side of the family.
On the 1861 census there were four month old twins Eleanor and (another) Theresa Annegarn who both died as babies in 1861 and 1862 respectively. There was another child, Florence, aged 4, who also died in the same quarter in 1862 as Theresa. It is therefore not surprising that the father went bankrupt in 1864, he must have been heartbroken.
Florence's husband died in 1919 and she died twenty four years later in 1943.
I have found Florence on a number of public member Ancestry trees and have sent a message to a few of the owners in the hope we will be able to repatriate the postcard with a living relative.
The story continues : A sad tale of scarlet fever
Facebook group : Every postcard tells a story