Faded family photo

My father told us that he had no family photos. More: he told me about how he´d had to flee through the back window of a cottage in Crete as the German army advanced towards his front door, and had left his photos behind. It was a surprise then to find them in a box n his attic after he died. I spent quite a while with them and using Ancestry.co.uk to identify the people in them.
This one´s not a problem. On the left of the photo, my father, Bill. To the right of him,  Nina (aka Chris), then Helen, then George. The photo was probably taken by their brother John. The youngest, John, was born in 1921, Bill in 1918, and George the eldest in 1910. George died in Karachi in 1937 so this photo can´t have been taken after 1936 or, judging by the ages, much before that either. ,
The photo´s faded. I´ve not tried to improve it - the fact of it´s fading feels right to me.
A brief history then - I´ll put the family gravestone (in the cemetery in Banff)  up as an extra.  Bill joined the RAF in 1938, fought in the war in the Middle East and Crete; and stayed in the RAF thereafter. Nina married an RAF officer and lived with him in Australia; she returned to the UK after his death in the late 1980s and died in the UK. Helen became a "fever nurse" at a hospital in Elgin, got pregnant (unmarried), was thrown out by her stepmother and moved to work in a hospital in Govan, Glasgow, where she died of TB in 1944. We don´t know what happened to her daughter but assume Helen made arrangements with the family of the father. George was murdered, in Karachi, by the husband of a Scottish woman, who then turned his gun on the police and finally shot himself. 
John died in the Mosquito he was piloting over France in the last days of the war. I´ll put a photo of John in the extras. 
That´s it, people. Family photos of people who, except the one, I never knew.