What's the "true story" about Craig-y-nos?

The other day my nephew was asked in a school exam to consider the following historical question in relation to child evacuees during the last war.

He was given a photograph of happy smiling children walking down a street on their way to their new homes. Alongside that he was also given an eye witness account, written in 1960 by a teacher who recalled the occasion as one of sadness with much weeping and mothers pursuing their departing children up the street.

Now the question he was asked was: which is the most useful ?

(Of course it begs the next question: useful for what? )
Nevertheless it got me thinking about the collection of over 1,000 digital photographas I possess which tell one story and the written accounts of ex-child patients which record in many cases a different version.

So, here's the question:
Which is the “true” story?
Because it is such a complex tale spanning nearly forty years of social and medical change I suspect there is no one "true story", but rather one of multiple perspectives.