I think the night solo and day solo together might be somewhat unique but I doubt that the 16 year old birthday solo student is.
I re-call one David Perrin, yes the very one, who on his 16th birthday just jumped into an RF4 at Biggin at about 0905, take-off and do an immaculate aeros display over the airfield. It would be 1970 I think.
I was one of two or three pilots who flew with him when he was a student, to keep him legal, but who could demonstrate then his immense skills. Twas a great day that.
Anyway, well done Chris. A very nice achievement.