No doubt someone will correct me if I'm wrong, but there cannot be any way that he has fully "earned" his wings after spending 4 months seconded to the RAF.
Did he ACTUALLY fly solo i.e. with just him in the aircraft?
Whereas I recall photos of his father and grandfather flying solo, the latter in this particularly good
PR-type photo,
I don't recall photos of Wills flying in an aircraft other than when he was accompanied by an instructor.