I agree that the defendant in a criminal case is entitled to have his lawyer argue that he's innocent if that's what the defendant wants. Even if that's perhaps not the "best" strategy at trial. It's the life and liberty of the defendant that's at stake. (Particularly, as here, in a prosecution for murder.) If the defendant wants to argue he's not guilty, he's got that right. Even if the defense counsel thinks -- perhaps correctly -- that the most effective way to present a defense would be to concede the events at issue and argue for voluntary manslaughter.
Now, here, the defendant was waffling a bit. This is not your prototypical case where the defendant consistently insists on X but the attorney goes and does Y. Still, the Court of Appeal is correct that the defendant had a desire and his counsel didn't follow it. That's generally sufficient -- on a critical issue like factual innocence, anyway -- to warrant a reversal.
Mind you, given the evidence, I'm fairly certain that the defendant will again be convicted at the retrial. The evidence against him was somewhat overwhelming.
But at least he'll get the joy of losing with his own strategy, as opposed to a strategy with which he disagreed.
Small solace, I know. But important.
(Parenthetically, the investigation of the crime here was far from perfect. After the stabbing, the police looked for the murder weapon in the apartment, but couldn't find it. Even though it was just sitting under the kitchen table. And they found fingerprints on the knife, but apparently didn't even bother to test them to see if they matched the defendant. Not the kind of police work you typically see in a murder case.)
