Thank you Arthur, Ruskie and Gadget for your continued interest in the mystery girl. I will try to respond to all of your suggestions and questions in one post.
The ones who lived in Yorkshire were Fred's niece Ethel Stell nee Dodson and her husband Edmund.
Both Ethel and Edmund are in the 4 photos I posted of the mystery girl at the seaside, also in several other photos I have been sent which appear to be taken at the same time. Ethel and Edmund are the older couple in photo no. 1 which appears to be in another garden, Ethel is wearing the same spotty dress she is wearing on the beach, so possibly the same day. I also think it looks like Ethel with her arm around the girl in photo 2.
So mystery girl was with Fred and Amory in Fred's Wolverhampton garden, and also at an unidentified seaside location with Fred's niece Ethel, her husband, other younger unknown adults and another child (boy or girl?).
I am beginning to think the nose similarity to Amory may be just coincidence. I can't find any link to Yorkshire for Amory's family as yet.
There is nothing to prove my F.I.L' s suggestion that she was a friend from Yorkshire, and after reading comments here I am now looking for other possibilities.
I have looked in the newspapers for obituaries/funeral reports for Fred and Amory but only found notices of the value of their respective estates when they died.
I have a few more ideas which I am following up. Does anyone recognise that beach? (I know the scans are not great, I am waiting for F.I.L to dig out the originals for me - could take some time

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