It's very kind of you to want to share your beautiful photo with it's 'model'!
From your description of the circumstances, it will be a very difficult task to track down this person and her young daughter.
What you might do, is post an advert in the local newspaper, describing the situation and date you visited Emmets Wood, and asking for the mother of the young girl you photographed among the bluebells to contact you because you would like to send her this photo. You might also publish the photo and ask if anyone knows this young girl, but it might be best to just explain the situation and hopefully, the mother will see your ad and respond. You might also ask your local tv news stations to run this story, show the picture you took, and explain that you're trying to make contact to share your beautiful photo.
If the girl and her mother were from the local area, these suggestions may help locate her.
I wish you much good luck!
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