He has expert witness, a sleep specialist doc who diagnosed parasomnia and agrees the whole episode is feasible.
He didn't exactly leave scene of collision as he didn't crash, just stopped, admittedly on top of a smallish roundabout, then ran home, oblivious.
Then he drank wine. The alcohol he consumed earlier pte driving was 1 pt, 2 g&t and a glass or 2 of Champagne. It is debatable whether that would have taken him over limit as he was driving around 4am and had had drinks around 11pm.
This may or may not have taken him over drink limit, we will never know.
How can they prove he was over limit taking these facts into consideration?
Barrister mentioning sane and insane, different outcomes, even though he is not insane the judge could still go that way, its an archaic law.