According to the book "A Spitfire Girl" the pilot's name was Flight Lieutenant Edward Gordon Brettell DFC of "Great Escape" fame, among other things, and he was court-martialed for flying his Spitfire Mark Vb of 92 Squadron to a dance with a WAAF on his lap. Squadron Leader Tony Bartley DFC helped defend him during the court-martial.
The man was a colorful character, to say the least. In one of the many references to him on the Internet I found this:
He had flown his girlfriend, a WAAF based at Tangmere, in his single
seat Spitfire to RAF Biggin Hill for a squadron party. Unfortunately
for him, the station commander who was there when they landed took a
dim view of his actions and reported him. Among the charges at his
later court martial was endangering the King's aircraft (King George
VI was then on the throne). He called upon his friend, a Battle of
Britain ace with a Hatfield-link, Anthony Charles Bartley (41816) for
Tony Bartley was acting as a test pilot for Supermarine at the time.
He later revealed in his autobiography that he asked Jeffrey Quill
(Supermarine's chief test pilot) and Joseph Smith (Supermarine's chief
designer after Reginald Mitchell's death) for their help. Joe Smith
even went so far as to draw up some mathematical equations alleged to
prove the aircraft wasn't in any danger, which Bartley presented at
the court martial. Although the clinching argument was when asked by
the prosecution how he could prove it, Bartley admitted to having
committed an identical offence previously. Now faced with the prospect
of having to prosecute two badly needed officers with a war on, the
charge was dismissed. Although Gordon Brettell was transferred away
from the squadron.