when Woffinden tried to find Michael Clark he discovered that he had left the country in 1965. However, Woffinden did manage to locate Clark's aunt, apparently his sole-surviving relative, who told him that Clark's hair was a 'general mousey colour', and not dark as Acott had recorded. Presumably she had lost contact with Clark by the time Woffinded found her.
We are suffering from a plethora of surmise, conjecture and hypothesis. - Sherlock Holmes, The Adventure Of Silver Blaze